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23+ Advanced JavaScript Interview Questions (ANSWERED)


Hungry for more advanced and tricky JavaScript Interview questions and answers to transform yourself from a Junior JavaScript Developer into a Senior JavaScript Guru before your next tech interview? Search no more! Come along and explore top hardest JavaScript Interview Questions and Answers including ES6, ES2015 for experienced web developer and get your next six-figure job offer.

Q1: Explain equality in JavaScript

Topic: JavaScript
Difficulty: ⭐

JavaScript has both strict and type–converting comparisons:

  • Strict comparison (e.g., ===) checks for value equality without allowing coercion
  • Abstract comparison (e.g. ==) checks for value equality with coercion allowed
var a = "42";
var b = 42;

a == b;            // true
a === b;        // false

Some simple equalityrules:

  • If either value (aka side) in a comparison could be the true or false value, avoid == and use ===.
  • If either value in a comparison could be of these specific values (0, "", or [] — empty array), avoid == and use ===.
  • In all other cases, you’re safe to use ==. Not only is it safe, but in many cases it simplifies your code in a way that improves readability.

🔗 Source: FullStack.Cafe

Q2: Provide some examples of non-bulean value coercion to a boolean one

Topic: JavaScript
Difficulty: ⭐⭐⭐

The question is when a non-boolean value is coerced to a boolean, does it become true or false, respectively?

"" (empty string)
0, -0, NaN (invalid number)
null, undefined
false

The specific list of “falsy” values in JavaScript is as follows:

Any value that’s not on this “falsy” list is “truthy.” Here are some examples of those:

"hello"
42
true
[ ], [ 1, "2", 3 ] (arrays)
{ }, { a: 42 } (objects)
function foo() { .. } (functions)

🔗 Source: FullStack.Cafe

Q3: What is IIFEs (Immediately Invoked Function Expressions)?

Topic: JavaScript
Difficulty: ⭐⭐⭐

It’s an Immediately-Invoked Function Expression, or IIFE for short. It executes immediately after it’s created:

(function IIFE(){
    console.log( "Hello!" );
})();
// "Hello!"

This pattern is often used when trying to avoid polluting the global namespace, because all the variables used inside the IIFE (like in any other normal function) are not visible outside its scope.

🔗 Source: stackoverflow.com

Q4: When should I use Arrow functions in ES6?

Topic: JavaScript
Difficulty: ⭐⭐⭐

I’m now using the following rule of thumb for functions in ES6 and beyond:

  • Use function in the global scope and for Object.prototype properties.
  • Use class for object constructors.
  • Use => everywhere else.

Why use arrow functions almost everywhere?

  • Scope safety: When arrow functions are used consistently, everything is guaranteed to use the same thisObject as the root. If even a single standard function callback is mixed in with a bunch of arrow functions there’s a chance the scope will become messed up.
  • Compactness: Arrow functions are easier to read and write. (This may seem opinionated so I will give a few examples further on).
  • Clarity: When almost everything is an arrow function, any regular function immediately sticks out for defining the scope. A developer can always look up the next-higher function statement to see what the thisObject is.

🔗 Source: stackoverflow.com

Q5: What are the differences between ES6 class and ES5 function constructors?

Topic: JavaScript
Difficulty: ⭐⭐⭐

Let’s first look at example of each:

// ES5 Function Constructor
function Person(name) {
  this.name = name;
}

// ES6 Class
class Person {
  constructor(name) {
    this.name = name;
  }
}

For simple constructors, they look pretty similar.

The main difference in the constructor comes when using inheritance. If we want to create a Student class that subclasses Person and add a studentId field, this is what we have to do in addition to the above.

// ES5 Function Constructor
function Student(name, studentId) {
  // Call constructor of superclass to initialize superclass-derived members.
  Person.call(this, name);

  // Initialize subclass's own members.
  this.studentId = studentId;
}

Student.prototype = Object.create(Person.prototype);
Student.prototype.constructor = Student;

// ES6 Class
class Student extends Person {
  constructor(name, studentId) {
    super(name);
    this.studentId = studentId;
  }
}

It’s much more verbose to use inheritance in ES5 and the ES6 version is easier to understand and remember.

🔗 Source: github.com/yangshun

Q6: Explain Function.prototype.bind.

Topic: JavaScript
Difficulty: ⭐⭐⭐

Taken word-for-word from MDN:

The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.

In my experience, it is most useful for binding the value of this in methods of classes that you want to pass into other functions. This is frequently done in React components.

🔗 Source: github.com/yangshun

Q7: What’s a typical use case for anonymous functions?

Topic: JavaScript
Difficulty: ⭐⭐⭐

They can be used in IIFEs to encapsulate some code within a local scope so that variables declared in it do not leak to the global scope.

(function() {
  // Some code here.
})();

As a callback that is used once and does not need to be used anywhere else. The code will seem more self-contained and readable when handlers are defined right inside the code calling them, rather than having to search elsewhere to find the function body.

setTimeout(function() {
  console.log('Hello world!');
}, 1000);

Arguments to functional programming constructs or Lodash (similar to callbacks).

const arr = [1, 2, 3];
const double = arr.map(function(el) {
  return el * 2;
});
console.log(double); // [2, 4, 6]

🔗 Source: github.com/yangshun

Q8: Explain the difference between Object.freeze() vs const

Topic: JavaScript
Difficulty: ⭐⭐⭐

const and Object.freeze are two completely different things.

  • const applies to bindings (“variables”). It creates an immutable binding, i.e. you cannot assign a new value to the binding.
const person = {
    name: "Leonardo"
};
let animal = {
    species: "snake"
};
person = animal; // ERROR "person" is read-only
  • Object.freeze works on values, and more specifically, object values. It makes an object immutable, i.e. you cannot change its properties.
let person = {
    name: "Leonardo"
};
let animal = {
    species: "snake"
};
Object.freeze(person);
person.name = "Lima"; //TypeError: Cannot assign to read only property 'name' of object
console.log(person);

🔗 Source: stackoverflow.com

Q9: What is generator in JS?

Topic: JavaScript
Difficulty: ⭐⭐⭐

Generators are functions which can be exited and later re-entered. Their context (variable bindings) will be saved across re-entrances. Generator functions are written using the function* syntax. When called initially, generator functions do not execute any of their code, instead returning a type of iterator called a Generator. When a value is consumed by calling the generator’s next method, the Generator function executes until it encounters the yield keyword.

The function can be called as many times as desired and returns a new Generator each time, however each Generator may only be iterated once.

function* makeRangeIterator(start = 0, end = Infinity, step = 1) {
    let iterationCount = 0;
    for (let i = start; i < end; i += step) {
        iterationCount++;
        yield i;
    }
    return iterationCount;
}

🔗 Source: stackoverflow.com

Q10: When should we use generators in ES6?

Topic: JavaScript
Difficulty: ⭐⭐⭐

To put it simple, generator has two features:

  • one can choose to jump out of a function and let outer code to determine when to jump back into the function.
  • the control of asynchronous call can be done outside of your code

The most important feature in generators — we can get the next value in only when we really need it, not all the values at once. And in some situations it can be very convenient.

🔗 Source: stackoverflow.com

Q11: Explain what is hoisting in Javascript

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐

Hoisting is the concept in which Javascript, by default, moves all declarations to the top of the current scope. As such, a variable can be used before it has been declared.

Note that Javascript only hoists declarations and not initializations.

🔗 Source: https://github.com/kennymkchan

Q12: What will be the output of the following code?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐

var output = (function(x) {
  delete x;
  return x;
})(0);

console.log(output);

Above code will output 0 as output. delete operator is used to delete a property from an object. Here x is not an object it’s local variable. delete operator doesn’t affect local variable.

🔗 Source: github.com/ganqqwerty

Q13: What will be the output of the following code?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐

var Employee = {
  company: 'xyz'
}
var emp1 = Object.create(Employee);
delete emp1.company
console.log(emp1.company);

Above code will output xyz as output.
Here emp1 object got company as prototype property.
delete operator doesn’t delete prototype property.

emp1 object doesn’t have company as its own property. You can test it like:

console.log(emp1.hasOwnProperty('company')); //output : false

However, we can delete company property directly from Employee object using delete Employee.company or we can also delete from emp1 object using __proto__ property delete emp1.__proto__.company.

🔗 Source: github.com/ganqqwerty

Q14: Explain the Prototype Design Pattern

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐

The Prototype Pattern creates new objects, but rather than creating non-initialized objects it returns objects that are initialized with values it copied from a prototype – or sample – object. The Prototype pattern is also referred to as the Properties pattern.

An example of where the Prototype pattern is useful is the initialization of business objects with values that match the default values in the database. The prototype object holds the default values that are copied over into a newly created business object.

Classical languages rarely use the Prototype pattern, but JavaScript being a prototypal language uses this pattern in the construction of new objects and their prototypes.

🔗 Source: dofactory.com

Q15: What is the Temporal Dead Zone in ES6?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐

In ES6 let and const are hoisted (like var, class and function), but there is a period between entering scope and being declared where they cannot be accessed. This period is the temporal dead zone (TDZ).

Consider:

//console.log(aLet)  // would throw ReferenceError

let aLet;
console.log(aLet); // undefined
aLet = 10;
console.log(aLet); // 10

In this example the TDZ ends when aLet is declared, rather than assigned.

🔗 Source: github.com/ajzawawi

Q16: Can you describe the main difference between a .forEach loop and a .map() loop and why you would pick one versus the other?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐

To understand the differences between the two, let’s look at what each function does.

forEach

  • Iterates through the elements in an array.
  • Executes a callback for each element.
  • Does not return a value.
const a = [1, 2, 3];
const doubled = a.forEach((num, index) => {
  // Do something with num and/or index.
});

// doubled = undefined

map

  • Iterates through the elements in an array.
  • “Maps” each element to a new element by calling the function on each element, creating a new array as a result.
const a = [1, 2, 3];
const doubled = a.map(num => {
  return num * 2;
});

// doubled = [2, 4, 6]

The main difference between .forEach and .map() is that .map() returns a new array. If you need the result, but do not wish to mutate the original array, .map() is the clear choice. If you simply need to iterate over an array, forEach is a fine choice.

🔗 Source: github.com/yangshun

Q17: What’s the difference between a variable that is: null, undefined or undeclared? How would you go about checking for any of these states?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐

Undeclared variables are created when you assign a value to an identifier that is not previously created using var, let or const. Undeclared variables will be defined globally, outside of the current scope. In strict mode, a ReferenceError will be thrown when you try to assign to an undeclared variable. Undeclared variables are bad just like how global variables are bad. Avoid them at all cost! To check for them, wrap its usage in a try/catch block.

function foo() {
  x = 1; // Throws a ReferenceError in strict mode
}

foo();
console.log(x); // 1

A variable that is undefined is a variable that has been declared, but not assigned a value. It is of type undefined. If a function does not return any value as the result of executing it is assigned to a variable, the variable also has the value of undefined. To check for it, compare using the strict equality (===) operator or typeof which will give the 'undefined' string. Note that you should not be using the abstract equality operator to check, as it will also return true if the value is null.

var foo;
console.log(foo); // undefined
console.log(foo === undefined); // true
console.log(typeof foo === 'undefined'); // true

console.log(foo == null); // true. Wrong, don't use this to check!

function bar() {}
var baz = bar();
console.log(baz); // undefined

A variable that is null will have been explicitly assigned to the null value. It represents no value and is different from undefined in the sense that it has been explicitly assigned. To check for null, simply compare using the strict equality operator. Note that like the above, you should not be using the abstract equality operator (==) to check, as it will also return true if the value is undefined.

var foo = null;
console.log(foo === null); // true
console.log(typeof foo === 'object'); // true

console.log(foo == undefined); // true. Wrong, don't use this to check!

As a personal habit, I never leave my variables undeclared or unassigned. I will explicitly assign null to them after declaring if I don’t intend to use it yet. If you use a linter in your workflow, it will usually also be able to check that you are not referencing undeclared variables.

🔗 Source: github.com/yangshun

Q18: Describe the Revealing Module Pattern design pattern

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐⭐

A variation of the module pattern is called the Revealing Module Pattern. The purpose is to maintain encapsulation and reveal certain variables and methods returned in an object literal. The direct implementation looks like this:

var Exposer = (function() {
  var privateVariable = 10;

  var privateMethod = function() {
    console.log('Inside a private method!');
    privateVariable++;
  }

  var methodToExpose = function() {
    console.log('This is a method I want to expose!');
  }

  var otherMethodIWantToExpose = function() {
    privateMethod();
  }

  return {
      first: methodToExpose,
      second: otherMethodIWantToExpose
  };
})();

Exposer.first();        // Output: This is a method I want to expose!
Exposer.second();       // Output: Inside a private method!
Exposer.methodToExpose; // undefined

An obvious disadvantage of it is unable to reference the private methods

🔗 Source: scotch.io

Q19: What’s the difference between ES6 Map and WeakMap?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐⭐

They both behave differently when a object referenced by their keys/values gets deleted. Lets take the below example code:

var map = new Map();
var weakmap = new WeakMap();

(function() {
    var a = {
        x: 12
    };
    var b = {
        y: 12
    };

    map.set(a, 1);
    weakmap.set(b, 2);
})()

The above IIFE is executed there is no way we can reference {x: 12} and {y: 12} anymore. Garbage collector goes ahead and deletes the key b pointer from “WeakMap” and also removes {y: 12} from memory. But in case of “Map”, the garbage collector doesn’t remove a pointer from “Map” and also doesn’t remove {x: 12} from memory.

WeakMap allows garbage collector to do its task but not Map. With manually written maps, the array of keys would keep references to key objects, preventing them from being garbage collected. In native WeakMaps, references to key objects are held “weakly“, which means that they do not prevent garbage collection in case there would be no other reference to the object.

🔗 Source: stackoverflow.com

Q20: Is JavaScript a pass-by-reference or pass-by-value language?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐⭐

It’s always pass by value, but for objects the value of the variable is a reference. Because of this, when you pass an object and change its members, those changes persist outside of the function. This makes it look like pass by reference. But if you actually change the value of the object variable you will see that the change does not persist, proving it’s really pass by value.

Example:

function changeStuff(a, b, c)
{
  a = a * 10;
  b.item = "changed";
  c = {item: "changed"};
}

var num = 10;
var obj1 = {item: "unchanged"};
var obj2 = {item: "unchanged"};

changeStuff(num, obj1, obj2);

console.log(num);
console.log(obj1.item);    
console.log(obj2.item);

Output:

10
changed
unchanged

🔗 Source: stackoverflow.com

Q21: How to “deep-freeze” object in JavaScript?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐⭐

If you want make sure the object is deep frozen you have to create a recursive function to freeze each property which is of type object:

Without deep freeze:

let person = {
    name: "Leonardo",
    profession: {
        name: "developer"
    }
};
Object.freeze(person); // make object immutable
person.profession.name = "doctor";
console.log(person); //output { name: 'Leonardo', profession: { name: 'doctor' } }

With deep freeze:

function deepFreeze(object) {
    let propNames = Object.getOwnPropertyNames(object);
    for (let name of propNames) {
        let value = object[name];
        object[name] = value && typeof value === "object" ?
            deepFreeze(value) : value;
    }
    return Object.freeze(object);
}
let person = {
    name: "Leonardo",
    profession: {
        name: "developer"
    }
};
deepFreeze(person);
person.profession.name = "doctor"; // TypeError: Cannot assign to read only property 'name' of object

🔗 Source: medium.com

Q22: In JavaScript, why is the “this” operator inconsistent?

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐⭐

The most important thing to understand is that a function object does not have a fixed this value — the value of this changes depending on how the function is called. We say that a function is invoked with some a particular this value — the this value is determined at invocation time, not definition time.

  • If the function is called as a “raw” function (e.g., just do someFunc()), this will be the global object (window in a browser) (or undefined if the function runs in strict mode).
  • If it is called as a method on an object, this will be the calling object.
  • If you call a function with call or apply, this is specified as the first argument to call or apply.
  • If it is called as an event listener, this will be the element that is the target of the event.
  • If it is called as a constructor with new, this will be a newly-created object whose prototype is set to the prototype property of the constructor function.
  • If the function is the result of a bind operation, the function will always and forever have this set to the first argument of the bind call that produced it. (This is the single exception to the “functions don’t have a fixed this” rule — functions produced by bind actually do have an immutable this.)

🔗 Source: stackoverflow.com

Q23: Compare Async/Await and Generators usage to achive same functionality

Topic: JavaScript
Difficulty: ⭐⭐⭐⭐⭐

  • Generator function are executed yield by yield i.e one yield-expression at a time by its iterator (the next method) where as Async-await, they are executed sequential await by await.
  • Async/await makes it easier to implement a particular use case of Generators.
  • The return value of Generator is always {value: X, done: Boolean} where as for Async function it will always be a promise that will either resolve to the value X or throw an error.
  • Async function can be decomposed into Generator and promise implementation like:

🔗 Source: stackoverflow.com

Categories
Javascript

Top FrontEnd JS Framework to learn in 2020

2019 can be described as the revolutionary year for JavaScript frameworks, as we saw huge development of these frameworks and the beginning of their use among the masses.

Read more to keep yourself updated with the frameworks that are predicted to rise.

What is JavaScript Framework?

JavaScript is a programming language that is commonly used for the development of moderate applications. It is lightweight and supported by the majority of the browsers we use in our daily life. It supports both Object-Oriented programming(OOPs) and Procedural programming. Hence, it is used commonly for making web pages with the client-side script to interact with the user and make the web pages effective and concise.

Framework

It is nothing but a large part of a code that you can apply to your code to some problem that you are facing in a specific domain. It can be used by providing “callbacks“.

Advantages of JavaScript Frameworks

  • It has strong community support which keeps it always updated.
  • Possess extensions that help in debugging components.
  • Plenty of third party component support.
  • The efficiency of the code increases.
  • It is free and open to use for all.
  • Possesses the ability to keep the user interface in synchronization with the state of the system.

2019 being such a great year for JS, what does 2020 have in store for us??

Now that we have discussed the JavaScript Frameworks, let us check out the rising frameworks in 2020:

1.Angular

Angular

Angular is an open-source application framework, which works on TypeScript. It has been developed and maintained by Google and released back in 2016 when there weren’t many framework applications. Due to this, it was the most widely used software back then. To date, it has 6 versions- Version 2, version 4, Version 5, Version 6, Version 7, Version 8. Although its position has decreased because of the launch of new frameworks, it is still one of the top 3 most widely used frameworks around the world and companies prefer to hire people who have the knowledge of Angular,

Advantage

  • Very reliable due to the support from Google.
  • A large number of tools for performing actions.
  • The quality of programming is high.
  • Good quality code generation.

Disadvantage

  • It requires a lot of knowledge about the software before working on it.
  • It consumes a large amount of energy.
  • Poor optimization of problem-solving, leading to low productivity.

2.React

React

The current leader of all the framework fields, React is developed by Facebook developers. It was launched completely in November last year while a prototype was launched back in 2013. It is based on reusable components. Most of the companies use it as their primary framework tool. It was the fastest-growing application in the framework field last year and is supposed to maintain that growth in 2020 too. Most of the developers speak in the same voice that React is easy to learn given that you have basic knowledge of JavaScript.

Advantage

  • Highly Adjustable.
  • Files composed are of small size.
  • Has a good JavaScript library.
  • Good stability.

Disadvantage

  • Documentation is not very fluent.
  • Proper study is required to use the extra tools to use them for coding.

3.Vue

Vue

Vue is an Open-source JavaScript-based framework that is mostly used for building software interface for the users. It was released in February 2014. Its creator, Evan You, worked for Google and used Angular. He noticed how heavy the framework was and when he created Vue, he made sure that it would be lighter than Angular. At 20KB in size, it has the smallest size among all frameworks. Due to this, it is rapidly growing but it still has a long way to the top.

Advantage

  • Fast Installation.
  • Ridiculously small size.
  • The study of components before coding is not required.
  • Simple to use.
  • It offers a lot of extensions to code with.
  • Blends with other programming languages without any problem.

Disadvantage

  • A small community of users and developers.
  • Less amount of tools.
  • Highly fluctuating.

4.Meteor

Meteor

Meteor is a free and open-source Framework based in JavaScript written in Node. It has the ability to produce cross-platform code among different platforms. It was released in 2012 and had a good growth rate but its growth was stalled by frameworks like Angular and React.

Advantage

  • Generates Cross-Platform code.
  • Easy to use.

Disadvantage

  • Lack of user and developer community.

5.Svelte JavaScript

Svelte Javascript

Svelte is a framework that is used for creating code. Its main developer is Richard Harris. Due to its small size, its speed gets increased many folds.

Advantage

  • Small Size.
  • Fast speed of operation.
  • It can exist separately with the code which was created by it.
  • Easy to use.
  • It requires less amount of memory.

Disadvantage

  • Very small community.
  • Limited functions and tools.

6.Ionic

Ionic

Ionic framework is a complete open-source Software Development Kit (SDK) for hybrid mobile development created by Max Spiery, Ben Sperry, and Adam Bradley of Drifty Co. in 2013. The pilot version was built on AngularJS and Apache Cordova. However, the latest release was re-built as a set of Web Components

Advantage

  • It is supported by all the platforms.
  • It allows the user to build applications.
  • Big companies like PayPal use it.
  • The Ionic framework provides a command-line interface (CLI) to create projects.

Disadvantage

  • This framework requires time to learn it.
  • It is a little complex compared to other frameworks.
  • It is not very secure when compared to other frameworks.
  • Specific plugins have to be developed.

7.Ember

ember

Ember is an open-source JavaScript Framework based on Model-view-view-Model (MVVM). It is used by websites like Apple, Twitch, Groupon, and Linkedin. It is owned by Tilde Incorporated and was launched in 2011

Advantage

  • It contains built-in testing tools.
  • Good community support from users and developers.
  • It is capable of giving high performance.
  • Its performance is good

Disadvantage

  • It requires a lot of study for doing coding on it.
  • Even after a large community, development speed is slow.

Conclusion

The frameworks mentioned above are the ones to be watched for the year 2020. But that does not mean the other frameworks are bad. It just means that they require a few modifications in their setup. Who knows they might be the one to watch out next year. But out of the frameworks mentioned, the ones to be observed with a close eye would be Angular, React and Vue.

Categories
Javascript

Javascript Frameworks you should definitely learn in 2020

Javascript has come out to be one of the most prominent languages for the past few years, especially after the rise of NodeJS. Since Javascript is the only language supported by browsers, there is no denying the fact that web development needs expertise in Javascript.

And with Javascript being supported in the backend, this came as a huge benefit as a single function/library/utility, which can be shared across both frontend and backend. Hence development time and resources are reduced.

With an increase in the use of javascript, many people are opting in to use javascript and the language is evolving faster and bringing the best of all the world. Be it Typescript, Promises, async awaits, these features come in very handy when doing enterprise development.

Backend Frameworks of Javascript you should learn in 2020

Express, or NestJS (Typescript)

Expressjs

Express JS is the de-facto for the NodeJS, a web application framework built by  TJ Holowaychuk. NestJS is the wrapper on top of the express js which has multiple other plugins that come handy when doing an enterprise-level project. And not to forget that NestJS come out of the box with typescript support and Dependency injections.

The framework structure is very similar to that of angular 2+, so in case you know either of one, the other one would be really fast to grab.

A big difference is that though Nest js use express under the hood, express is a callback-based framework, whereas nest mostly use promises and async-await, so codes are pretty neat.

So, if you are going to do an MVP and need to move really fast and stick to just plain es6 or es7, I would recommend sticking to Express. But if you can give more time and compatibility with typescript, I would strongly recommend using nestjs, as it comes with ‘out-of-the-box’ multiple supported integrations.

Here is a quick demo on how you can use nestjs with typeorm ( ORM for SQL Database connections). And you can clone the same codebase and remove the parts which you are not going to use.

TypeORM

typeorm

The database is a very crucial part of almost any web or backend development. Writing queries and managing connections become really a nightmare as the project scales, and if there is any need for changing database servers, it means you have to go through all the queries and connection handling. To avoid such things and keep the code really clean, we use the ORM layer.

The two major ORMs for Node are Sequelize and TypeORM.

TypeORM support typescript out of the box and comes with both Datamapper and ActiveRecord support out of the box.


Though typeORM is very new, has an active development and still, in alpha production, it is yet quite stable and can be used for enterprise-level projects.

NestJS come out pretty handy when integrating TypeORM as if they are meant to go side by side. I won’t be surprised if NestJS start using TypeORM as its default ORM Layer.

Here is a quick tutorial on how you can use TypeORM with One-to-one, one-to-many, many-to-many relationships with any SQL server using NestJS.

GraphQL, Apollo Server

GraphQL

GraphQL was developed at Facebook and is being used intensively for data-driven web apps. Though many backend languages and framework support graphql, to date only NodeJS has the best integration with the apollo server.

So, if you are going to do GraphQL web development, Nodejs is generally the first preference for development for the backend.

NestJS provides a pretty clean GrapQL plugin, that can be integrated and can use to start development.


Though GraphQL is generally preferred to be used over the No-SQL database, it’s not that it is meant to be done by No-SQL only. But it can do pretty well with SQL servers and TypeORM on top of it.

Though in some cases you might need to integrate the DataLoader for optimization of queries and take that extra relational feature of the SQL server.

Here is q quick tutorial on how you can use GraphQL with NestJS and Typeorm and Dataloader

If you know the above three frameworks, you can do almost any kind of web or backend development

Frontend Frameworks of Javascript you should learn in 2020

Front_end frameworkds

React Native for Web

There is no denying the fact that React & React-native have been in major use, but with flutter pushing flutter web and to write single code for the native as well as web apps, there is a definitive need for a similar framework which does the same.

Thanks to Necolas for starting this project, which has around 15.5k stars on Github. Though this framework is not widely used it’s going to be a breakthrough in 2020, where you can just maintain a single codebase for all your mobile and web apps.

If you already know React or React-Native, then React Native web is just a morning coffee for you, and you can directly start building apps by using its documentation.


Here you can read a brief introduction of the react-native web.

You might have to struggle a bit with some libraries, but it’s not a deal-breaker. You can read more about a happy struggle with react native web

If you know Expo and have been doing react native development on top of Expo, you can follow the guide here, Does expo support react native web

Here is a quick comparison guide on react native web vs react

React, React-native ( NextJs for server-side rendering)

React & React native still rule the web and app development. You can read the related topics here

Why learning react native makes sense in 2020

Angular

angular

If you want to build an enterprise-level project, I would recommend going for Angular. And, the main reason angular still is the first preference for enterprise or a huge project is that it comes with a lot of juices out of the box.

The first and foremost is the support for typescript out of the box. It also supports dependency injection and the framework is very well-enabled with guards, services, interceptors, middleware that can be directly plugged in and can be taken advantage of.

You can read in details about the difference between angular and react here

If you noticed above, we have recommended NestJs as a backend framework. If you know NestJS, then the good news is NestJS is actually inspired by Angular, so if you know one of these, learning the other would be really fast and nice.

If you are looking to get started with angular, here is a quick guide on Guide To Your First Angular 5 App

Frequently Asked Questions

Categories
Backend Developer Database Javascript Node

25 Interview Questions on Node.js

Here we listed down the most asked interview questions on Node js so that you don’t have to go anywhere. This is a one-stop destination for all your queries. We provide you the top 25 interview questions on Node js so you can ace your interview. Let’s just look at the questions below.

1. What is Node js?

The first and most asked question is what is Node js?. Node js is an open-source server environment that uses javascript to make web software that is computationally simple but is easily accessed. It works really fast and can run on different platforms like Windows, Linux, Mac OsX, etc

2. What are some key benefits to Nodejs?

There are numerous benefits of Node js which are explained as follows.

  1. It is fast because it is built on Google chrome’s V8 JavaScript engine which makes it really fast.
  2. Node js has no buffering and no blocking while working. It output the data in chunks.
  3. It is Asynchronous meaning Nodejs never stops for an API to return the data. It is ready to take the next request.

3. Is Node js single-threaded? If yes, then why?

Well yes and actually no. NodeJS is single-threaded since no two functions can be run at the same time. Although, a running program called a process can have multiple threads. NodeJS runs only one program at a time to implement its asynchronous nature of program execution hence a single-threaded server environment but can a program can use multiple threads internally to yield optimal performance hence a multi-threaded server environment.

4. What type of applications you can build using Node js?

  • Streaming apps
  • Chat applications
  • Internet of things
  • Microservices
  • Collaboration tools
  • You just name it and we can build it using Node.js

5. How the content of a file is read by Node js?

The NodeJS’s fs (file-system) module provides an API to interact with the system files. The files can be read with multiple methods available to us. In the example below, we will be using the readfile method of fs module to read the contents of a file.

var fs = require(‘fs’);

fs.readFile(‘DATA’, ‘utf8’, function(err, contents) {

    console.log(contents);

});

console.log(‘after calling readFile’);

if you want to know in synchronous manner then have a look in this sample

var fs = require(‘fs’);

var contents = fs.readFileSync(‘DATA’, ‘utf8’);

console.log(contents);

 

6. Discuss the streams in Nodejs? And what are the different types of streams?

Streams are something that allows the reading and writing of data from source to destination in a continuous process.

Streams are of 4 types

·         <Readable> that promotes reading operation

·         <Writable> that promotes writing operation

·         <Duplex> that promotes above both

·         < Transform> is a kind of duplex stream which does the computation based on available input.

7. What is closure?

A closure is a function that is sustained in another scope that has access to all other variables in the outer scope.

8. Does Zlib use in Nodejs? If yes, then why?

Yes, Zlib used in Nodejs and Zlib was written by Jean-loup Gailly and Mark Adler. It is a cross-platform data compression library. You need to install a node- Zlib package in order to use Zlib in Nodejs. A sample is given below which shows the code to use Zlib. 

var Buffer = require(‘buffer’).Buffer;

var zlib = require(‘zlib’);

var input = new Buffer(‘lorem ipsum dolor sit amet’);

var compressed = zlib.deflate(input);

var output = zlib.inflate(compressed);

9. Discuss the globals in Node.js?

Globals basically comprise three words which are Global, Process and Buffer. Let’s discuss it one by one.

Global–  As the name is suggesting Global is something which has many things under its umbrella. So it’s a namespace object and act as an umbrella for all other objects < global>

 Process– It is a specified type of Global and can convert Asynchronous function into an Async callback. It can be linked from anywhere in the code and it basically gives back the information about the application.

 Buffer– Buffer is something that is known as a class in Nodejs to tackle the binary data.

 

10. Differentiate between Nodejs and Ajax?

Ajax is used on a specific section of a page’s content and update that specific portion rather than updating the full part of the content.

Nodejs, on the other hand, used for developing client-server applications. Both of the above serve different purposes and these are the upgraded implementation of JavaScript.

11. What is Modulus in Node Js?

Modules are a reusable block of code whose existence doesn’t impact alternative code in any means. it’s not supported by Javascript. Modules come in ES6. Modules are necessary for Maintainability, Reusability, and Namespacing of Code.

12. What do you mean by an event loop and how does it work?

An event loop tackles all the callbacks in any application. It is the vital component of Nodejs and the main reason behind the non- blocking I/O. Since Node.js is associate event-driven language, you’ll be able to simply attach an observer to an occurrence so once the event happens the callback is executed by the precise observer.

13. What is callback hell?

Callback Hell is additionally referred to as the Pyramid of Doom. it’s a pattern caused by intensively nested callbacks that square measure unreadable and unwieldy. It usually contains multiple nested request functions that successively build the code exhausting to browse and correct. it’s caused by improper implementation of the asynchronous logic.

query(“SELECT clientId FROM clients WHERE clientName=’picanteverde’;”, function(id){

  query(“SELECT * FROM transactions WHERE clientId=” + id, function(transactions){

    transactions.each(function(transac){

      query(“UPDATE transactions SET value = ” + (transac.value*0.1) + ” WHERE id=” + transac.id, function(error){

        if(!error){

          console.log(“success!!”);

        }else{

          console.log(“error”);

        }

      });

    });

  });

});

14. What are the types of API functions in Nodejs?

There are mainly two types of API functions, one is blocking function and the other is non- blocking function.

Blocking function:  These functions implement synchronously and all other code is blocked from implementing until an I/O event that is being waited occurs.

For instance

const fs = require(‘fs’);

const data = fs.readFileSync(‘/file.md’); // blocks here until file is read

console.log(data);

// moreWork(); will run after console.log

Non-blocking Functions: These functions implement ASynchronoulsy and in this multiple, I/O calls can be executed without being waited for.

For instance

const fs = require(‘fs’);

fs.readFile(‘/file.md’, (err, data) => {

  if (err) throw err;

  console.log(data);

});

// moreWork(); will run before console.log

Since fs.readFile () is non-blocking, moreWork () does not have to wait for the file read to complete before being called. This allows for higher throughput.

15. What is Chaining in Nodejs?

Chaining is a system where one stream has an output and that is connected with the output of another stream that creates a chain-like formation of multiple stream operations.

16. Explain the Exit codes in Nodejs? Name some of the exit codes?

As the name is suggesting exit codes are those codes that are used to end the Process where process means a global object that represents a node process.

There are some exit codes given below.

  • Fatal error
  • Uncaught fatal Exception
  • Internal javascript Evaluation failure
  • Non-function internal exception handler
  • Unused
  • Internal exception handler Run-time Failure.

17. What is the working of control flow function?

Control flow function in Nodejs is a code that is implemented between Asynchronous function calls. There are some steps given below which must be followed while implementing it.

  • First, the order of execution must be controlled
  • Second,  collection of the required data is must,
  • Third, concurrency must be limited.
  • When the above process is done the next step of the program is requested.

18. Differentiate between readfile and createReadSTream in Nodejs?

  • Readfile loads complete file that you have marked to read on the other hand createReadStream reads the complete file in the pieces you have declared.
  • CreateReadStream works faster than Readfile. The client will get slower data in the latter one.
  • In Createreadstream, it first read by memory in parts the client will get a part of data that is read and this process will continue until it finishes but in Readfile a file is read by memory completely then the client will get it.

19. How to update a new version of NPM in Nodejs?

For this, you have to give a command for updating in Nodejs

$ sudo npm install npm -g

/usr/bin/npm -> /usr/lib/node_modules/npm/bin/npm-cli.js

npm@2.7.1 /usr/lib/node_modules/npm

20. How to prevent/ fix callback hell?

There are three ways to prevent fix callback hell

Handle every single error

Keep your code shallow

Modularize – split the callbacks into smaller, independent functions that can be called with some parameters then joining them to achieve desired results.

The first level of improving the code above might be:

var logError = function(error){

    if(!error){

      console.log(“success!!”);

    }else{

      console.log(“error”);

    }

  },

  updateTransaction = function(t){

    query(“UPDATE transactions SET value = ” + (t.value*0.1) + ” WHERE id=” + t.id, logError);

  },

  handleTransactions = function(transactions){

    transactions.each(updateTransaction);

  },

  handleClient = function(id){

    query(“SELECT * FROM transactions WHERE clientId=” + id, handleTransactions);

  };

query(“SELECT clientId FROM clients WHERE clientName=’picanteverde’;”,handleClient);

You can also use Promises, Generators and Async functions to fix callback hell.

21. What is the procedure to handle child threads in Nodejs ?

In general, Node.js could be a single-threaded method and doesn’t expose the child threads or thread management ways. however, you’ll still build use of the child threads victimization spawn() for a few specific asynchronous I/O tasks that execute within the background and don’t sometimes execute any JS code or hinder with the most event loop within the application.

22. What are the different timing features of Nodejs?

Node.js gives a Timers module that contains different functions for executing the code after a stipulated period of time. There are some features of different timing that are given below.

setTimeout/clearTimeout –  It is Used to schedule code execution after a specific amount of milliseconds

setInterval/clearInterval – Used to implement a block of code multiple times

setImmediate/clear Immediate – Used to implement code at the end of the current event loop cycle

process.nextTick – Used to schedule a callback function that needs to be requested in the next repetition of the Event Loop.

23. What is the usage of buffer class in Nodejs?

Buffer category in Node.js is employed for storing the raw information similar manner of an array of integers. However, it corresponds to a raw memory allocation that’s settled outside the V8 heap. it’s a worldwide category that’s simply accessible will be accessed in AN application while not importation a buffer module. Buffer category is employed as a result of pure JavaScript isn’t compatible with binary knowledge.

24. What is the role of REPL in Nodejs?

REPL stands for Read, Eval, Print, Loop. The REPL in Node.js is used to implement ad-hoc Javascript statements. The REPL shell allows entry to javascript directly into a shell prompt and evaluates the results. For the purpose of testing, debugging, or experimenting, REPL is very critical.

25. What is libuv in Nodejs

libuv is a Cross-platform I/O abstraction library that supports asynchronous I/O based on event loop. It is written in C and released under MIT Licence.

libuv support Windows IOCP, epoll(4), kqueue(2), and Solaris event ports. Initially, it was designed for Node.js but after that, it is also used by other software projects.

Categories
Angular Development Frontend Developers Javascript Node React Developers ReactJS

23 JavaScript Interview Questions And Answers

JavaScript is a high-level, dynamic, untyped, and interpreted programming language. It has been standardized in the ECMAScript language specification. Alongside HTML and CSS, it is one of the three essential technologies of World Wide Web content production; the majority of websites employ it and it is supported by all modern web browsers without plug-ins or any kind of other extensions.

“Javascript is the duct tape of the Internet.”

Let’s starts with some common Qs about JavaScript.

  • JavaScript is developed by- Netscape Communications Corporation Mozilla Foundation, Ecma International.

  • It designed by- Brendan Eich

  • JavaScript is called- JS

  • The extension filename of JavaScript- .js

  • JavaScript Media type- application/javascript, text/javascript.

  • The current version of JavaScript- ECMAScript 2018.

In this guide, you’ll find example interview Qs and answers you can refer to when seeking a new JavaScript developer to make your dynamic user interfaces come to life. You’ll also get some practical Qs on how to use these Qs to reliably identify results.

Q 1. Is JavaScript and JScript the same?


Answer. Both JavaScript vs JScript is designed to make dynamic web pages and interactive content.

  • Javascript is a scripting language (supports scripts) for Web pages but it is also used in non-browser environments as well. It is a powerful, lightweight, interpreted, scripting language with first-class functions (i.e. the language supports passing functions as arguments to other functions).
  • JScript is also a scripting language, much similar to JavaScript. It is a dialect of the popular ECMAScript standard reverse-engineered by Microsoft. JScript is subsidy by Microsoft and used in one of the most popular web browsers Microsoft’s Internet Explorer. JScript can also be called “Microsoft’s JavaScript”.
DifferenceJavaScriptJscript
TypeScripting languageScripting language owned by Microsoft.
SimplicityIt needs to write scripts manually. Same as JavaScript in this context.
Browser
Compatibility
It needs to handle multiple
browsers compatibility.
Only support by Microsoft’s internet
explorer.
Active Content
Creation
Does not support active content
creation.
With JScript, you can create active
online content for WWW.
Object
Access
JavaScript cannot access web browser
objects.
JScript can easily access-
objects exposed by internet explorer.

Q 2. Justify the use of let and const in JavaScript?


Answer. Earlier in javascript, developers use the var keyword for creating variables. let & const keyword is introduced in version ES6 with the vision of creating two different types of variables in javascript one is immutable and the other is mutable. The use if let and const in JavaScript:

  • let

let is used for variable declaration as it comes as an improvement to the var declarations. let is a block code bounded as {}. So a variable declared in a block with the let is only available for use within that block.

  • Example:
let greeting = "say Hi";
   let times = 4;

   if (times > 3) {
        let hello = "say Hello instead";
        console.log(hello);//"say Hello instead"
    }
   console.log(hello) // hello is not defined
  • const

Variables declared with the const maintain constant values. const declarations share some similarities with let declarations.

Like let declarations, const declarations can only be accessed within the block it was declared in.

const cannot be updated or re-declared

This means that the value of a variable declared with const remains the same within its scope. It cannot be updated or re-declared. So if we declare a variable with const.

  • Example:
const greeting = "say Hi";
    greeting = "say Hello instead";//error : Assignment to constant variable. 

Q 3. Explain the MUL function in JavaScript?


Answer. MUL means a simple multiplication of numbers. It is a technique in which you pass one value as an argument in a function and that function returns another function to which you pass the second value and the process goes on. Multiplies two expressions. This is the functional equivalent of the (*) operator.

Q 4. List the Frameworks and Data types supported by JavaScript?


Answer. The frameworks used by JavaScript are:

  • Node.js
  • Angular.js
  • React
  • Vue.js
  • Ember.js
  • Meteor
  • Backbone.js

Data types supported by JavaScript are:

  • Symbol
  • String
  • Boolean
  • Null
  • Undefined
  • Number
  • Object

Q 5. How you can redirect a page to another page in JavaScript?


Answer. There are several ways to redirect the page to another page in JavaScript. These are:

  • Using location.href: It is the first approach to redirect page. In this, we can go back to access the original document.

  • Using location.replace: Another approach to redirect page. In this, it is not possible to navigate back to the original document by clicking on the back button as it removes the URL of the original document. 

Q 6. Clarify some design patterns in JavaScript?


Answer. The design pattern is a reusable solution to a commonly occurring problem in software design. Some of the design patterns are:

  1. Behavioral Patterns: 
    These patterns are to improve communication between objects and to recognize patterns. Visitor, states, strategy, Memento, Mediator, Iterator, Command, Chain of responsibility and observer are examples of Behavioral patterns.

  2. Creational design pattern: 
    These patterns deal with the mechanism of object creation which optimizes object creation with the basic approach. Factory method, Abstract Factory, Builder, Prototype, and Singleton are the categories of Creational design pattern.

  3. Concurrency design patterns: 
    These patterns handle with multi-thread programming paradigms. Some popular categories of concurrency design patterns are Scheduler, Nuclear reaction, and Active object.

  4. Structural design pattern: 
    These patterns deal with different classes and objects to provide new functionality. Adapter, Bridge, Composite, Decorator, Facade, Flyweight, and proxy are the categories od structural design patterns.

  5. Architectural design patterns: 
    These patterns used to deal with architectural designs. Like: MVC (Model-View-Controller), MVVM (Model-View-ViewModel), and MVP (Model-View-presenter).

Q 7. Explain promise in JavaScript?


Answer. A Promise is a proxy for a value not necessarily known when the promise is created. It allows the developers to associate handlers with asynchronous action’s eventual success value or failure reason. Essentially, a promise is a returned object that you can attach callbacks to, instead of passing callbacks into a function.

  • 3 states to a promise:
  1. pending: awaiting promise response.
  2. resolve : promise has successfully returned.
  3. reject: failure occurred.
  • Syntax:
new Promise(executor);
Function process of promise

Q 8. What are the advantages of using JavaScript?


Answer. Some key advantages of JavaScript are:

  • JavaScript is an easy language to learn.

  • It is comparatively fast for the end-user.

  • Easy to debug and test.

  • JavaScript is platform-independent.

  • It works on the client6-side.

  • Also, has powerful frameworks.

  • Event-based programming language.

  • Procedural programming capabilities.

Q 9. How to get inner HTML of an element in JavaScript?


Answer. InnerHTML property of HTML DOM is used to get inner Html of an element in JavaScript.

  • Example:
<script type="text/javascript">
	var  inner= document.getElementById("inner").innerHTML ;
	console.log(inner); // This is inner Element
	document.getElementById("inner").innerHTML = "Html changed!";
	var  inner= document.getElementById("inner").innerHTML ;
	console.log(inner); // Html changed!
</script>

Q 10. What are the Arrow functions in JavaScript?


Answer. Arrow functions were introduced in ES6. Arrow functions allow the developers to write shorter function syntax.

hello = () => {
  return "Hello World!";
}

An arrow function expressions is a syntactically compact alternative to a regular function expression, but this function has its own bindings to the arguments, super, this, and new.target keywords.

Q 11. How to encode and decode a URL in JavaScript?


Answer. Encode and Decode a URL in JavaScript:

  • encodeURI() function is used to encode an URL in Javascript.It takes a url string as parameter and return encoded string. Note: encodeURI() did not encode characters like / ? : @ & = + $ #, if you have to encode these characters too please use encodeURIComponent().

    Usage:
var uri = "my profile.php?name=alex&occupation=danciNG";
var encoded_uri = encodeURI(uri);
  • decodeURI() function is used to decode a URL in Javascript. It takes an encoded URL string as a parameter and returns decoded string.

    Usage:
var uri = "my profile.php?name=alex&occupation=danciNG";
var encoded_uri = encodeURI(uri);
decodeURI(encoded_uri);

Q 12. Classify the different ways of empty an array in javascript?


Answer. In Javascript, there are many ways to empty an array, here are the four major ways to empty an array:

  • By poping the elements of the array.
var arr2 =[1,4,5,6];
while(arr.length > 0) {
    arr.pop();
}
  • Assigning array length to 0.
var arr2 =[1,4,5,6];
arr2.length=0;
  • Using .splice().
var arr =[1,4,5,6];
arr.splice(0,arr.length)
  • By assigning an empty array.
var arr1 =[1,4,5,6];
arr1=[];

Q 13. How to remove duplicates from JavaScript Array?


Answer. The three main approaches to remove duplicates from JavaScript Array:

  • By using Set:

It is the simplest way to remove duplicates because Set is an inbuilt object to store unique values in an array.

How to use set:

 function uniquearray(array) { 
       let unique_array= Array.from(set(array)) 
       return unique_array;}

By this code, you can easily create a set of an array that automatically eliminates duplicate values in JavaScript.

  • By using Filter:

This is another way to remove duplicates from an array. In the Filter method, it requires three arguments: Current element, Index of the current element, and Array.

How to use Filter:

function unque_array (arr){
 let unique_array = arr.filter(function(elem, index, self) {
 return index == self.indexOf(elem); } 
return unique_array }
 console.log(unique_array(array_with_duplicates));
  • By using for loop:

This is also a way to remove duplicates, but in this developer make an empty array in which those elements will be added from the duplicate array to get the unique elements.

Code use as:

Array dups_names = ['Tom', 'Pal', 'Fred', 'Rongo', 'Ron'];
function dups_array(dups_names) {
 let unique = {};
 names.forEach(function(i) {
    If (!unique[i]) {
      unique[i] = true;    }
  });
return Object.keys(unique);}   // Tom, Pal, Fred, Rongo
Dups_array(names);

Q 14. Are the results of 6 + 4 + ‘45’ and 6 + 4 + 45 the same?


Answer. No, the results should be different from each other because the results for the two statements are very different from each other. 6 + 4 + 45 gives the result 55, which is the expected answer for the addition of numbers. But, 6 + 4 + ‘45’ returns 1045 as a result. This is because 45 is a string and 6 and 4 are numbers. The presence of the string specifies that the + operator is a string operator for concatenation rather than an arithmetic operator.

Q 15. What is null, undefined, and undeclared JavaScript variable?


Answer.

  • Null

It can be assigned to a variable to represent no value. It is an assignment value.

var b = null;
console.log(b); //null
console.log(typeof b); //object
  • Undefined

It means a variable has been declared but has not yet been assigned a value

var a;
console.log(a); //undefined
console.log(typeof a); // undefined
  • Undeclared

If a variable is not declared then the browser throws an error.

console.log(nonDeclaredVariable);
 
// Uncaught ReferenceError: nonDeclaredVariable is not defined
//    at <anonymous>:1:13
 
console.log(typeof nonDeclaredVariable); //undefined

Q 16. What is the purpose of ‘This’ operator in JavaScript?


Answer. The JavaScript this keyword refers to the object it belongs to. This has different values depending on where it is used. In a method, this refers to the owner object and in a function, this refers to the global object.

Q17. Explain the terms synchronous and asynchronous code.


Answer. The synchronous code is something that should be finished before anything else can happen, or in other words, the synchronous code is blocking. And the Asynchronous code is something in which actions can happen and is not dependent on other actions- in other words, it is non-blocking.

Q 18. Are “==” and “===” operators different in JavaScript?


Answer. “==” checks only for equality in value whereas “===” is a stricter equality test and returns false if either the value or the type of the two variables are different. So, the second option needs both the value and the type to be the same for the operands.

Q 19. How to Calculating the Fibonacci series in JavaScript?


Answer. Fibonacci Series is a sequence of numbers where the first two Fibonacci numbers are 0 and 1, and each subsequent number is the sum of the previous two.

function fibonacci(n) {
let arr= new Array(n+1);
arr[1]=1;
arr[2]=1;
for(let i=3;i<=n;i++)
{
 arr[i]=arr[i-1]+arr[i-2];
}
for(let i=1;i<=n;i++)
{
 console.log(arr[i]);
}
return;
} 


Answer. The process of Create, Read, and Delete a cookie by using JavaScript:

  • Cookie creating process-

The simple way to create a cookie is to assign a string value to the document.cookie object.

Syntax:

document.cookie = "key1 = value1; key2 = value2; expires = date";
  • Reading a cookie-

It is just as simple as writing one for the developers because of the value document.cookie object is the cookie. So you can use this string whenever you want to access it.

This fulfills your two conditions:

  1. The document.cookie string will keep a list of anme= value pairs separated by semicolons.

  2. It is easy for the developers to use the string’s split() function to break the string into key and values.
  • Delete a cookie-

If you want to delete a cookie, that subsequent attempts to read the cookie return nothing, you just need to set the expiration date to a time in the past. You should define the cookie path to ensure that you delete the right cookie. Some browsers will not let you delete a cookie if you don’t specify the path.

Q 21. Consider the following code:

function test() {
console.log(a);
console.log(foo());
var a = 1;
function foo() {
return 2;
}
}
test();

What is the result of executing this code and why?

Answer. The result of this code is undefined and 2.

The reason is that both variables and functions are hoisted but variables don’t retain any assigned value. So, at the time the variable “a” is printed, it exists in the function but it’s still undefined. Stated in other words, the code above is equivalent to the following:

function test() {
var a;
function foo() {
return 2;
}
console.log(a);
console.log(foo());
a = 1;
}
test();

Q 22. List the comparison operators supported by JavaScript?


Answer. The comparison operators are:

  • < Less than
  • > Greater than
  • <= less than or equal to
  • >= Greater than or equal to
  • == Equal to
  • != Not Equal to
  • === Equal to with datatype check
  • !== Not equal to with datatype check

Q 23. How you can clone an object in JavaScript?


Answer. Object.assign() method is used for cloning an object in Javascript.

Syntax:

 var x = {myProp: "value"};
 var y = Object.assign({}, x); 

Categories
Backend Developer Development Express Javascript Node

What Really Makes Node.js Great?

Javascript- That is actually playing a drastic role to make Node.js great. As it is well known that Javascript is favorite to most of the software developers to build applications because Node.js uses javascript as its main framework. The Node.js community is used to create a scalable application.

After specialising in Ruby on Rails for a while, I realised that the time has come for me to expand my skill set. I wanted to move on from working move on from working mostly on small-scale apps into more ambitious projects for large corporate clients. Node.js was the obvious choice, because I already knew JavaScript and was aware that the market value of Node.js skills would only grow.

-Michal Hartwich
nodejs


Why Node.js is a standard programming language to enterprises for large-scale apps?

REASONS:

  1. Make real-time applications fast.
  2. In node.js coding in JavaScript is possible for both the client and server-side.
  3. Increase efficiency in the developing process.
  4. Execution of coding is faster than other languages and boost productivity.
  5. As well as perfect for Microservices.

You read about Node.js and its uniqueness that makes it great among all. Lets first start with the intro part.

Why it is great?

Node.js is a cross-platform, and open-source, JavaScript run-time environment that executes JavaScript code outside the browser. Though .js is a filename extension for JavaScript, that allows the developer to use Javascript to write the command lines for server-side scripting to produce dynamic web page content.

Corporate users of Node.js software are LinkedIn, Netflix, Microsoft, and so on. As Node.js has an event-driven architecture that capable of asynchronous I/O (It is a form of input/output processing that permits other processing to continue before the transmission). It aims to optimize scalability in web applications.

Helping Hands- Node.js Frameworks:


To smoothen your application development, here are some excellent Node.js frameworks to build your applications more effectively.

1. Design your web application with Express.js


Express is a web application framework for Node.js developed by T J Holowaychuk. It is free and open-source software under the MIT License. It is designed to build web applications and APIs.

The other name for Express.js is a minimalist framework. It is a single-threaded, open-source and fast Node.js framework used for web and mobile app designing. This framework is easy to understand. It allows easy integration of third-party services and seamless I/O approach.

Several NPM modules can be integrated into Express.js for better operations. The back-end of a MEAN stack is developed by Express.js and MongoDB, with AngularJS in the front-end. Express.js is described by an event loop and non-blocking I/O.

2. Developer supportive- Nest.js


Nest.js is a server-side (backend) application framework to support the developer’s productivity. Nest framework is a TypeScript characterized by Dependency injection, authentication, stack, ORM and REST API.

nestjs


Development with TypeScript using nest.js employs code writing by juxtaposing various programming types such as functional programming, object-oriented programming, functional reactive programming, etc. However, the tools used in nest.js need improvement for enhanced performance.

It is an event-based that allows the scalability of microservices. Nest.js provides the developer flexibility that allows using any libraries of Node.js. It is versatile as well as progressive.

3. Ironic Meteor.js


This Node.js framework employs isomorphic JavaScript code for mobile and web app development. Meteor.js is an MVC-based and open source and provides a highly effective front-end solution. It allows a highly efficient client-server interface, seamless debugging, live reload, database integration and real-time testing.

Meteor.js

Though it has few loop-holes like lack of server-side rendering, the absence of in-build PWA support, the absence of MongoDB support, etc. , meteor.js still stands out as an excellent framework with its simplicity and versatile libraries and packages.

OMG! It amazes the developer’s experience.


Node.js is used for real-time application and Node.js is open source cross-platform runtime environment has been written in JavaScript. The top choice of a developer in the web application development is Node.js because it comes with new features.

It also allows developers to make web servers and networking tools with effective use of JavaScript.

  • Node.js Is Very Fast:

Node.js use V8 engines by Google. Google engines V8 (JavaScript → V8(C++) Machine Code) which compile JavaScript into native machine code and runs very speedy and because of it, Node.js increase any framework’s speed. It helps enterprises build fast, flexible network applications that can handle parallel connections with high throughput.

  • Stimulate Sharing:

Node.js boosts imparting to the approach the Node Package Manager or NPM. With the inbuilt NPM, developers can restore, share or reuse codes within with clicks. Along these lines, it tends to be proved that Node.js bundle supervisor is strong and a steady answer for designers.

  • Node.js Make For Real-Time Web Application:

It has unbelievable features when it comes to creating real-time applications such as chats and gaming apps. Also good for the programs that need an event-based server, as well as non-blocking driven servers.

  • Single Code Base Web Application:

The developer writes JavaScript for server and client, by making it easy to send data between the server and the client for synchronization.

  • Data Streaming:

Web frameworks treat HTTP requests and responses as whole data objects. Node.js is very good at handling I/O, So it can use as an advantage for the developer to build some amazing web application. Node.js can also read and write streams to HTTP.

  • Every Developer Know JavaScript:

Every web coder has coded a little bit of JavaScript, even if that JavaScript was hacking a jQuery plugin. Nowadays, it is hard to find web developers. And Node.js is easy to learn if the developer familiar with JavaScript.

  • Increase Productivity:

Productivity must not be sighted as a one-dimensional character, but a multidimensional one. A developer is more productive in Java because of compile-time errors. Enterprises can add the frontend and backend teams into a single unit so application delivers in less time with high productivity.

Even if we had a language that made writing callbacks easy (like C#), we’d need a platform that minimal to no blocking I/O operations.

Node.js- What So Special..!!

The Node.js server technology is used to create & run high variety of web applications, it is quite similar to Ruby on Rails does. Its main language is JavaScript which is lightweight and manages the plenty plugins via Node Package Manager (NPM), that allows the developers to custom-build applications.

There are no different languages for back-end and front-end developers, Node.js uses the same language for both of them that make it easy to create apps.

The Back-end applications directly interact with the database via an application programming interface (API) that pulls, saves, or changes data, whereas the Front-end codes interact with back-end sever to drag out the data on the front-end user interface (UI) side.

But with Node.js, both (Front-end and Back-end) merged and work together instead of pulling each other to different directions of working.

Every developer is familiar with JavaScript which is the main reason for Node.js to build and compile applications easily, there is no other language to create or build any API and UI applications in node.js. It decreases the complexity by performing the code.

Node.js boost both front-end and back-end and acts as the best of technology to develop apps. This means that your team will be more efficient and cross-functional leading to lower development costs. In addition to this, it is worth mentioning that JavaScript makes your codebase with much easier platforms. Secondly, you can also then reuse and share the code between the backend and the frontend of your application that speeds up the development process.

The complete js technology stack is open-source & free and that is good news. Finally, Node offers you a complete package for every possible thing that developers are looking for.

TOP 5 SEARCH ENGINE QUERIES ON NODE.JS


Why Node js is Used?

Node.js is an excellent platform built on Chrome’s JS runtime for developing, building a fast, scalable for network applications.

Is Node.js a programming language?

Node.js connects the efficiency of a scripting language with the power of Unix network programming. It is proficient with internet fundamentals such as HTTP. Therefore, Node.js is not a programming language but a Scripting language in JavaScript.

Is Node.js same as JavaScript?

Simply, JavaScript is a programming language that runs in any browser of JavaScript Engine, but on the other hand, Node.js is an interpreter of JavaScript, which holds the relative or you can say similar libraries of it for better use. So, they are not the same but, follows similar libraries to build applications.

What is Great about Node js?

The great thing about Node.js is, it uses event-looping instead of the strings. Excessing web services, reading along with the files and then making a file to wait until it’s completely get uploading because such operations are mostly slow then the memory execution operations. Every input/output operation in the Node.js is asynchronous. Sever continue to process all the Input-output operations. It makes scaling and processing between the programming events easy.

What are the benefits of using node.js for a startup?

benefits of Node.js:
1. Node.js is scalable.
2. It boosts your development speed.
3. Requires a low learning curve if you are familiar with JavaScript.
4. Take less time to run any program.

Categories
Development Frontend Developers Javascript Node ReactJS Startup Top Coder

Nuxt, Next, Nest! Confused?

Programming is the method to innovate something new and amazing. Being a coder, it is important to be aware of every new upcoming technology. “Nuxt”, “Next”, “Nest” a little confusing, right? They might sound similar but their practical application is different from each other.

The coders who aren’t familiar with these frameworks might get confused in the beginning, these are the perplexed and complex words. I’m going to explain all the concepts of Nuxt, Next, and Nest so stay tuned with me, in this article you may explore the uses and the installation of these frameworks. Surely, this article will help you to know about these frameworks in depth.

Do you ever think why do we actually need a framework? What are the uses of the framework?

  • A framework is a platform that provides a foundation on which software developers can create programs. It allows the coder to make robust applications.

  • Also, the framework provides diversified support for developing robust applications with pace and ease because it provides a standard way to build and deploy applications.

Before starting with these frameworks, let’s have a short briefing of CSR (client-side rendering) vs SSR (Server-side Rendering).

  • By these platforms, it is important to understand that Vue and React are the client-side Rendered (CSR) framework, which makes the page interactable and viewable.

WORKING OF CSR

📤 Server sending the response to the browser 📤

📥 Browser downloads JavaScript 📥

💬 Browser executes React 💬

🌐 The page now viewable and interactable 🌐

  • Using these platforms, Server-side Rendered (SSR) use to make the page interactable.

WORKING OF SSR

👩‍💻 Server sending ready to be rendered
HTML response to the browser
👩‍💻

📥 The browser renders the page, Now viewable
and browser downloads JavaScript
📥

🆗 Browser executes React 🆗

🌐 Page now Interactable 🌐

The first thing that needs to be clear is these three frameworks- Nust, Next, and Nest are different from each other but comes in Javascript Ecosystem.


If you’re a Vue.js programmer, then you probably heard of Nuxt.js. or if you’re not then let starts with Nuxt!

What is Nuxt.js?


Nust.js is a high-level framework that builds on Vue. It is an open-source application framework that is free and based on Vue.js, also Node.js, Webpack, and Babel.js. Nust comes under universal application which uses “meta-framework” as well as develops single page Vue apps.

The main aim to build applications with Nuxt.js that it is more flexible while creating any project because Nuxt helps the developers to create complex, fast, and universal web applications quickly.

What is Vue.js?

It is an open-source Javascript framework, it is faster as well as smoother to build user interfaces and single-page applications. The reason behind this is, Vue had familiar templating syntax and use of components, integrating or migrating the project make it more understanding by the beginners. For this reason, Vue is the best framework for tech startups or beginners to learn and build applications. Also, useful for large-scale applications as performance-wise.

[Important] The current version of Nuxt.js is v2.9.2

Reasons why the developers consider Nuxt for any project:

1. Build universal apps without any trouble.


The plus point of the Nuxt.js is that the developers can create universal applications easily in the Vue. Most of the people are not familiar with universal apps basically the beginners.

So, what is a universal app?

It is the app that describes JavaScript code that can execute both on the client and the server-side. There are many modern Javascript frameworks like Vue, that aim to build Single-page Applications (SPA). And a universal app completely based on SPA.

  • Nuxt makes coding more simple:

    It is boring to build long monotonous projects for developers because it needs more time for the configuration on both server-side and client-side. The main aim is to make it simple to share codes between server and client.

    Last but not least, Nuxt gives the developer an asyncData method in the components which use to fetch data and render it on the server-side. This is how Nuxt helps the developers to create universal applications.

2. Provide automatic code-splitting


Nuxt generates a static version of your website with a unique webpack configuration. For every page, it automatically creates the program which builds its own JavaScript file.

Also, it helps to speed up the progressing and keep the size of the JavaScript file small relatively to the application size.

3. Easy to write Single file components


There are many Vue projects using Vue.component, supported by new Vue ({ el: `#container’ }) to target the container element in the body of every page. It is used only to build small projects (single file) where JavaScript is only used to enhance certain views. It has difficulty managing the big file. Use .vue extension with single-file components, to solve your problem.

The installation process of Nuxt.js

  • Syntax to Install Nuxt:
$ npm i nuxt
  • Syntax to create a basic application:
$ npx create-nuxt-app <project-name>

According to the latest update, you can directly start with the CLI create-nuxt-app.

Or start it with a simple template: starter:
The basic Nuxt.js project template express: Nuxt.js + Express koa: Nuxt.js + Koa adonuxt: Nuxt.js + AdonisJS micro: Nuxt.js + Micro nuxtent: Nuxt.js + Nuxtent module for content-heavy sites.

  • Example: Syntax for a basic Hello World app in Nuxt.js
<template>
  <div>
    <h1>Hello world!</h1>
    <NLink to="/about">
      About Page
    </NLink>
  </div>
</template>

Advantages of Nuxt.js

  • The main advantage of Nuxt.js is, its main scope is UI rendering while removing away the client/server distribution.

  • In Nuxt.js you get automatic code-splitting.

  • Statically its render your Vue apps and get all of the benefits of a universal app without a server.

  • You can easily set up transitions between your routes and write single-file components.

  • It provides an auto-updating server for easy development.

  • In Nuxt.js you get ES6/ES7 compilation without any other extra work.

After clear our first concept of Nuxt. Let’s move to the next topic Next.js

next.js


If you compare all three frameworks, the most popular framework you get is Next.js from the other two. Let see what is so interesting in this framework that it is popular and developer’s favorite.

What is Next.js?


Next.js is a Javascript framework that uses React to build server-side rendering and static web applications. According to every developer, it the best tool to build websites because it has great features and advantages, which make it the first option for creating web applications.

So, do you think, why it is the first choice of the developer for building web applications?

The first thing that makes it different from the other two frameworks is it doesn’t need any configuration of webpack. Even it comes with its configuration, with some basic React and Javascript knowledge, build your way to development.

Some of you all know about React, but for beginner, let’s have a quick introduction to React.

What is react?

React is a Javascript library for building user interfaces, it is also known as React.js. It can be used as a base in the development of single-page or mobile applications that make it optimal for fetching rapidly changing. React was created by Facebook.

For using React.js it is important to know about the basic components of React.

Components cab be rendered to a particular element in the DOM by using the React DOM library. There are two primary components in React.

  • Functional components

These are the component which declared with a function that then returns some JSX.

Syntax:

function Greeting(props) {
  return <div>Hello, {props.name}!</div>;
}
  • Class-based components

These are the components declared using ES6 classes and also known as “stateful” components, because their state holds the values throughout the component and can be passed to child components through props.

Syntax:

class ParentComponent extends React.Component {
  state = { color: 'green' };
  render() {
    return (
      <ChildComponent color={this.state.color} />
    );
  }
}

This is all about React let come to our topic Next.js.

Next.js is a framework that is opinionated and provides a structure for the apps. As well as it is an automatic code-splitting.

[Important] The current version of Next.js is Next.js 9

Some reasons to use Next.js to build your project.


Next.js comes with great features that make it useful as well as popular among the developers.

1. Easy to generate website


For beginners or experienced developers, Next.js is the framework easy to use and get started to build a project. It is easy in Next.js to compile and export the application in HTML.

2. Server-side rendering


Next.js performs server-side rendering by default which makes your application optimized for search engines. In this Next.js come with a head component that allows the developers to add or make dynamic Meta-Tags.

By using SSR you get:

  • It provides users an initial render of the applications while loading the code in the background.
  • Easily eliminate the need for the client to download code in HTML format.
  • Also, help to create SEO friendly applications.

3. Routers


When you create any React application by using create-react-app, you usually need to install a react-router and create its custom configuration. But with Next.js it is easier because it comes with its own routers with zero configuration. The main feature is that Next.js take care of all its routers you just sit and create your page inside the pages folder.

The Installation Process of Next.js

  • Syntax to install Next.js:
npm install --save next react react-dom
  • Syntax to add a script to your package.json:
{
  "scripts": {
    "dev": "next",
    "build": "next build",
    "start": "next start"
  }
}

After that, the file-system is the main API. Every.js file program that gets automatically processed and rendered.

  • Example: Syntax for a basic Hello World app in Next.js

Use ./pages/index.js inside your project

function Home() {
  return <div>Hello world!</div>;
}

export default Home;

Then run npm run dev.

Advantages of using Next.js

  • Next.js is easy to deploy anywhere with Node.js support.

  • It can be executed with Express or any other Node.js HTTP server.

  • Any unnecessary code is not loaded in Next.js.

  • Webpack-based dev environment which supports Hot Module Replacement (HMR).

  • Fetch data easily.

  • Next.js is simple client-side routing (page=based).

  • Every component is server-rendered by default in Next.js.

  • As well as, automatic code-splitting which use for faster page loads.

Here we complete our two concepts Nust.js and Next.js, let’s move to the last topic Nest.js

nest.js


The main thing that makes Nest.js differ from both the frameworks is that it is heavily inspired by Angular.

What is Nest.js?


Nest.js is a framework for building efficient, scalable Node.js server-side applications. It is the modern JavaScript, which is built with TypeScript and uses Express.js. The important thing that Nest.js provides that it preserves compatibility with pure JavaScript and the combine elements of OOP (Object-Oriented Programming), FP (Functional Programming), and FRP (Functional Reactive Programming).

As similar to TypeScript and a reasonable knowledge of JavaScript help the developer to create the best application in Nest.js. The main aim of Nest.js was to solve the architectural problems of Node.js by providing back-end applications a modular structure for organizing code into separate modules. The plus point to work in Nest.js that it is fully built with TypeScript which is really beneficial for code type checking by which it helps to facilitate the process of development of the application.

[Imprtant] The current version of Nest.js is version5

Recently, the Nest.js framework is increasing popularity due to its incredible features:

Some features of Nest.js

  • Nest.js is open-source (MIT license).

  • It is easy to use, learn and develop applications.

  • It is a powerful command-line interface (CLI) tool that boosts your productivity.

  • It has detailed and well-maintained documentation.

  • Also, supports specific modules that help you easily integrate with common technologies and concepts such as TypeORM, Mongoose, GraphQL, Logging, Validation, Caching, and Websockets.

  • Also, provide active codebase development and maintenance.

  • Leverages typescript which means it is a strongly typed language that super-set of JavaScript.

  • Easy to unit testing applications.

  • The Nest.js is made for Monoliths and Micro-services (entire section in the documentation regarding the Microservice type of a NestJS application, as well as techniques and recipes).

Nest.js provide the developers with an out-of-the-box application structure that allows them to create highly testable, scalable and easily maintainable applications. As well as it makes use of Express which provides compatibility with a wide range of other libraries that the developer easily uses the myriad third-party plugins which are available.

The Installation of Nest.js

  • Syntax to install Nest.js
$ npm i @nestjs/cli
$ nest new project-name
  • Example: Syntax for basic Hello World app in Nest.js

    Remember, after installing Nest.js with the npm cli command, and to create a new project with nest new project-name.
import { NestFactory } from '@nestjs/core';
import { ApplicationModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(ApplicationModule);
  await app.listen(2000);
}
bootstrap();

And then to run the app listen on port 2000, you execute the syntax:

$ npm run start

Advantages of using Nest.js

  • The main advantage of the Nest.js is that it has a TypeScript-based web framework, that possible to build any strict type application.

  • The framework of Nest.js is very annotation-driven which generates everything to make you easy.

  • The project that builds in Nest.js is heavily based on Angular.

  • As you know Nest.js is a module-based framework, by which it is easy to externalize general-purpose modules and reuse code in multiple projects.

  • The important advantage of the Nest.js is that it uses the latest version of TypeScript that helps the developers to code less and gets productive work. And this is the same with Angular.

Just Remember

Nust– This is the framework to create a Vue application that supports universal rendering.

AND

Next- This is to create a React application that also supports universal rendering.

AND

Nest– This for node applications with additional structure and support.

Categories
Development Javascript React Native Web Top Coder

Should I Still Be a Programmer After 40?

Developers are equipped with multiple skills ranging from designing a new product to write complex code. And the age is just a number if you truly love your profession. There are many developers who think that what they do when they turn above 40.

According to Mr. Josan senior developer, here at Codersera says- “developing software is my passion which makes me younger and self-motivated after 45.”

Mr. Josan is one of our senior developer who says that “age is just a number”, if you have the potential to learn new technologies and continuously upgrade yourself with new trends. He is 45 years old and works with young people and manage his team perfectly. He works so energetically as well as handles the projects professionally without any ” “. With the experience of over 15 years as a software developer, he learned every new technology which came in the market and always updated his team with it.

“Once a programmer always a programmer.”


There is no age limit to be a programmer, it just depends on your skills and abilities to coding and innovate something new. As we know experience is also important. In every company, most of the employees are experienced and the companies also prefer experienced people in their team.

Why companies hire experienced developers?

  • More experience.
  • Easily handle the situations.
  • More familiar with coding languages.
  • Capable of managing a complex project.

Self-motivation is more important to continue your journey as a developer. There are many people who think that developers career is ended after 40, which is a hoax but they have more experienced and skilled to work. Even after 40, some people start their career as a developer and work as remote developers and freelancers, which give them the opportunity to follow their passion.

No one decides your career age for you or when will you retired from work. Not even the programming languages set their limits of learning. All you need is a chair, laptop, and working internet connection and you good to go.


How to enhance yourself with new technologies?


There are many developers who stop working after the age of 40. here we mention some point which can motivate you, here are some points that increase your interest and motivate you to continue your developing skills.

And after introspect and discussion with Mr. Josan, here I come up with very interesting techniques of motivation.

  • Never stop yourself from creating something new:

Being a developer, the first thing that you should keep in your mind is you never be afraid to face challenges. You know every line of code is written to create something new. The product you create is something that gives you the satisfaction of your hard work. And startups like Uber, Netflix, and Airbnb are some examples of how you can create something amazing with lines of code.

  • Never stop yourself from learning new technologies:

Python and r are beginner-friendly and their syntaxs are like simple English, and there are many online sources (paid and free) through which you can learn languages on your own.

Programming languages are upgraded fequently which make it learn with fun. Like React, React Native and then React Native web- these framework uses javascript as their base which makes them easier to learn. programming languages are easy to learn after you master any 1 programming language, for example: if you learn C++ you can easily learn Java, Python as the syntax changes but the logics remain the same.

Some sources where you learn programming languages.

  1. khan academy (Free)
  2. treehouse (paid)
  3. udemy (Paid)
  4. codecademy (Freemium)
  5. The New Boston (Free)
  • Never stop believing yourself:

Age never defines your abilities to learn, unless you believe in you. You are the developers who builds applications & software from the betterment of the future. don’t forget every new programmer was once a fresher and it’s not their age that got them where they are right now, it’s their passion towards creating something new using their coding skills. and once you start programming your passion along with your experience will take you to new heights or the programmer you wants to become.

  • Always respect your work:

Irrespective of your work profile you should always take pride the work you do. The programmers are proudly known by their intelligence and technical aptitude. For any tech organization, the developer’s opinions are very important especially when they are the serious or experienced one. Respect towards your work is a great motivator form you to even work after 40 or 50 years of age.

Job as a developer can be classified as a never-ending job if you never stop yourself to learning new skills and practice it. If you want to grow and last longer in your field of interest, the all you need to do is learn to adopt the latest technologies to increase your knowledge.

codersera


As shown in the graph, there are the maximum number of people are of age group 20-24 with 80% and less in >60 age group. It is because there are more developers of younger age and they have great and huge oceans of new ideas. So, the age group of people 20-24 has the highest percentage because at this age people are more energetic and familiar with new technologies and easily get things done.

The reasons- why companies prefer freshers?

  • New ideas
  • More productive work
  • Fast working abilities
  • Aware and use to with new technologies easily
  • Good knowledge of trends
  • Easily available


Freshers have considered more productive but old employees had huge experience to manage or handle any project alone. The best thing that happens in between them is new ideas and old experience build an amazing team.

As well as working with experienced persons, the freshers excellent knowledge and learn from their mistakes.

Categories
Angular Development Javascript Remote developer Startup Top Coder

Top 5 Programming Languages For Jobs And Future

So many programming languages- confused about what to choose or pursue as a job. In this article, every programming language is briefly described which make easy for you to choose and learn according to your interest.

Sometimes it is difficult to find the best out of the rest. Here are the top 5 programming languages and their job rates and future scope.

Before starting with languages, let’s brief that what is programming language is?

Introduction to Programming Language

The programming language is a language which contains a set of instructions that produce various kinds of outputs. It is used in computer programming to execute algorithms.

Thousands of different programming languages built and many more created every year but only a few implemented in the market or used by developers.

But only those programming languages, that are easy to use and understand. The classification of a programming language usually divided into two ingredients- syntax (form) and semantics (meaning).

Syntax

  • It is the surface form of a programming language.
  • Most of the programming languages are purely textual, so they use sequences of text including words, numbers, and punctuation.
  • The syntax of a language expresses the possible compounds/combination of symbols.

Semantics

  • The meaning of programming languages.
  • There are two types of semantics-
    (1) Static semantics: The static semantics defines restrictions on the structure of valid texts that are hard or impossible to express in standard syntactic formalisms. and
    (2) Dynamic semantics: The machine must be instructed to perform operations on the data. 

TOP PROGRAMMING LANGUAGES AND THEIR JOBS AND FUTURE SCOPES

The popularity of top programming languages


Several new programming languages are coming up that revised for different categories of developers (beginners, average, and experts). As well as for different use cases (web application, mobile applications, game development, distributed system, etc).

The most essential skill to learn in today’s scenario is how to write a computer program. The programming and developer community are emerging at a rate faster than ever before.

Python


It is a general-purpose programming language, which is used to build easy and tools and libraries. For backend web development, artificial intelligence, data analysis, and scientific computing- python is a great language.

There are many developers who use python and find it simple and easy to learning. Therefore, they have used python to build productivity tools, games, and desktop applications. 

Today, Python has multiple implementations including Jython, scripted in Java language for Java Virtual MachineIronPython has written in C# for the Common Language Infrastructure, and PyPy version written in RPython and translated into C.

While these implementations work in the native language they are written in, they are also capable of interacting with other languages through the use of modules. Most of these modules work on the community development model and are open-source and free.

Advantages/Benefits of Python


The various application of the Python language is a combination of features which give this language advantages.

  • Supportive Libraries: Python provides a large standard library which includes areas like internet protocols, string operations, web services tools, and operating system interfaces.
  • Presence of Third Party Modules: The Python Package Index (PyPI) contains numerous third-party modules that make Python capable of interacting with most of the other languages and platforms.
  • Productivity and Speed: Python has a clean object-oriented design which provides enhanced process control capabilities and possesses strong integration as well as text processing capabilities.
  • Open Source and Community Development: Python language is developed under an OSI-approved open source license, which makes it free to use and distribute, including for commercial purposes.
  • Learning Ease and Support Available: Python gives excellent readability and uncluttered easy-to-learn syntax which helps beginners to utilize this programming language. The code style guidelines, PEP 8, provides a set of rules which help to format the code.
  • User-friendly Data Structures: Python has built-in list and dictionary data structures which can be used to create fast runtime data structures. Secondly, it also provides the option of high-level data typing which decreases the length of the support code that is needed.

Career With Python

  • With many different programming languages available, Python has tremendously outraced the other languages.
  • Career opportunities associated with Python have also grown significantly as its popularity has increased by 40%.
  • Many IT businesses are looking for more candidates with experience and skills in Python programming languages.
  • This has illustrated the better career scope for the Python programmers in the near future.
Top Companies using Python Programming Language


Why Python has a bright future ahead?


Python has been voted for the most favourite programming language. It is assuredly beating other programming languages. It has been used for developing almost every kind of applications whether it is web applications or game applications.

[Important] Recently, on 2nd July 2019, Python 3.6.9 offers drastic improvement, among other new features. Python 3.7.4 is the current version of Python which is released on July 8, 2019.

JavaScript


JS is the high-level, interpreted scripting language which follows the ECMAScript specification. It is the multi-paradigm, supporting object-oriented, dynamic, imperative, declarative and a prototype-based language.

Even it’s used in many non-browser environments. Javascript is an easy and the language which use to design or program the webpages. Also, for controlling webpage behaviour.

In Javascript, the basic syntax, intentionally related to Java and c++ languages to reduce the number of new concepts required to learn this language.

But “Javascript has not interpreted java”. The language constructs are such as:
– if statements,
– for and while loops,
– switch, catch blocks function.

JS is the dynamic capabilities include runtime object construction, function variables, dynamic script creation, variable parameter lists, object introspection, and source code recovery. the common application for Javascript is the web server-side scripting language.

A Javascript web server would host object represents HTTP request and response objects for javascript program to generate dynamic web pages. The most popular example of Javascript is Node.js.

There are some databases like MongoDB and CouchDB which use Javascript as their programming language.

Different features of Javascript


Career with JS


There are so many options for freshers or experienced people:

  • Front-End web developer: This job focussed on HTML, CSS, JavaScript and light backend.
  • Web Application developer: Creating web-based software application including interactive online forms, shopping carts, word processing, Email software, and file conversions using Javascript.
  • Javascript developer: Designing and developing new front-end applications for various platform.
  • UX/UI designer: Design the product features according to users or clients. And find innovative ways to resolve UX problems as well as collaborate with UI designers to execute attractive designs.
  • Full-stack developer: Design the architecture of the web application.
  • DevOps engineer: This job is a link between IT and Developers like testing servers, deploying, version control, build processes and server software.

Advanced future of JS

No doubt that there are various frameworks (VUE.js, jQuery, Angualr.js, and React.js) that have their own established in the market which is constantly growing as well as some frameworks might fail in future and some continually grow.

Comparison of Javascript frameworks


Looking at the statistics and market position, it does not seem that react.js will leave its popularity in recent time as well as in the future.
The future, however, it will be a hybrid of everything available today. Where one framework, which is defined as the easiest to adopt by developers and proposes a complete solution, uses complementary techniques such as web components, web assembly, and AI, to create an end to end solution for developing applications.

JAVA


It is a general-purpose programming language that is class-based, and object-oriented. Java code can run anywhere or on all platforms that support Java without the need for recompilation. And Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM). The syntax of Java is similar to C and C++.

Java is one of the popular programming languages. it is a widely-used programming language that designed according to any distributed environment of the internet. As well as Java can be used for creating complete applications.

Java is popular because-

  • data is secure
  • easy to learn
  • code robust
  • applets give flexibility
  • portability in a network
  • object-oriented
  • platform-independent

Three main platforms of Java:

  • Java SE (Standard Edition)
  • Java EE (Enterprise Edition)
  • JavaME (Micro Edition)

[Important] The latest version is Java 12 which is released in March 2019.

Different features of Java

The Career path with JAVA


There are many career options with Java:

  1. Back-end developer: This career path is the one most in-demand and offers worldwide. As freelancer or remote developers or in-office, companies demand back-end developers for them and with a good salary package.
  2. Big data developer: This is fastly growing career option as most of the companies are looking for leveraging large data sets for various business and marketing.
  3. Android developer: An android programmer as a career is a really good option with java.
  4. Embedded devises developer: Using Java, this is a niche path which also has growth opportunities for the developers.
Developers position using Java

In the above graph, you find three years of representation of developers positions.
However, Java is the one outstanding Android versatile application that improving market. The popularity of Java is high than other programming languages.

Future of JAVA


No doubt that java would have an amazing future, as it is a future-oriented programming language for years. Secondly, Java has brought many new concepts in which the most significant one is the security of applications and programs. So, in the upcoming years, business organizations find Java applications more secure.

Ruby on Rails


It is an interpreted, high-level, general-purpose programming. Ruby is used to collecting garbage, it is a dynamic type language which supports multiple programming paradigms. Also, it includes procedural, object-oriented and functional programming.

Rails is a development tool that gives web developers a framework and a structure to write code. It simply helps to build websites and applications. ” Convention over configuration” is the key principle of Ruby.

Why developer go with Ruby on Rails?

  • Ruby is faster than other framework and language.
  • Same coding structure which makes coding easy for the developers.
  • Good for rapid application development (RAD) as well as easy to accommodate changes.
  • It developed a strong focus on testing.
  • Also, it has open-source libraries
Amazing features of Ruby

Boost your career with Ruby


As now ruby on rail becomes the popular programming language. Ruby on rails entry-level jobs is Junior programmer and co-developers. As well as the experienced person get the good opportunity of high-position jobs like chief technology officer, project leader, and senior developers. With these amazing jobs, they get an annual salary which is starts at $100,000 to $154,000.

Three levels:

  • The entry-level Ruby on Rails developer jobs includes setting up rail environment, managing database, handling requests, basic HTML, JavaScript, and CSS knowledge and performing basic tasks related to the development of Ruby on Rails application.
  • The mid-level RoR developer job requires you to have knowledge about ActiveRecord Associations, Design patterns, and Object Orientation.
  • The senior-level jobs in Ruby on Rails require the developers to have skills such as understanding of Ruby Metaprogramming, database modelling, monitoring skills, planning, and estimation.

Future track with Ruby on Rail


After watching the career scope of Ruby, it looks like Ruby has a huge and bright future because:

  • Apt for a low budget
  • Community
  • Easy testing
  • Consistency
Companies using Ruby on Rails

PHP


Hypertext Preprocessor (PHP) is a general-purpose programming language which is designed for web development. PHP code is usually processed by PHP interpreter as a module in the webserver secondly, the PHP code executed with a command-line interface (CLI). It is a scripting language that adopts to server-side web development. So, it can be used for client-side GUI and command-line scripting. Many web hosting providers support PHP for their clients. Also, PHP is free of cost.

The main use of PHP is that it acts like a filter, which takes input from text and converts it into output another stream. And it common output as HTML. PHP main focuses on the server-side scripting languages that provide dynamic content from a webserver to the client.

Some features of PHP

Why developers choose PHP?

  • PHP supports database management system and other open-source.
  • It also supports MySQL, Oracle, Sybase, etc.
  • It is simple and easy to learn.
  • Runs on platforms such as Linux, Windows, etc.

Career with PHP


Becoming a PHP developer can open several doors throughout your career. The first step up the ladder from this position is a senior web developer job.

In this role, your responsibilities encompass all aspects of creating websites and software, including supervision of PHP. From the position of a senior web developer, you can go on to become an IT manager, development director, Chief Technology Officer, or a senior .NET developer. These are just a few options you can take depending on your other qualifications.

Future of PHP

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Development Frontend Developers Javascript Node Remote developer

What is Scala used for? | A Brief Overview


Scala is a general-purpose, object-oriented programming language. It provides support to functional programming. It also helps in avoiding bugs in complex applications. In this article, you get to know about Scala and what is Scala used for?

Introduction

Scala is a programming language invented in the year 2003 by Mr. Martin Odersky and his team. Scala released publicly in 2004 on the Java platform. The name Scala is a blend of scalable and languages. That signifies it designed to grow with the demands of its users.

  • Scala is a Robust and High-Caliber programming language.
  • It is also capable to outrun the speed of the fastest existing programming languages.
  • it’s a compiler-based and a multi-paradigm language.
  • Which makes it compact, fast and efficient.
  • Scala uses Java Virtual Machine(JVM) for compilation.
  • Firstly Scala Compiler compiles the Scala code and generates the byte code for the same.
  • After that, it transferred to the Java Virtual Machine to generate the Output.

Platforms And Compilers


Scala runs on the Java Platform(JVM). So it is compatible with all the existing Java programs. Even its compatibility with JAVA makes it well-suited to Android development. Because Android applications typically write in Java and translate from Java bytecode into Dalvik bytecode when packaged.

Let’s talk about some Scala compilers:-


Scala.js:-

  • Scala.js is a Scala compiler.
  • It compiles to JavaScript.
  • Scala.js compiler makes it possible to write Scala programs that can run in web browsers and also in Node.js.
  • The compiler was in development since 2013. But launched in 2015 with the version name(v0.6).


Scala native:-

  • Scala native is also a Scala compiler.
  • That mainly targets the LLVM compiler infrastructure to create executable code.
  • It uses a lightweight managed runtime. Its first release was 0.1 on 14 March 2017.
  • The motive behind developing scala native is being faster than JIT compilation for the JVM.
  • It achieved by eliminating the initial runtime compilation of code and also providing the ability to call native routines directly.

Key Features Of Scala

  • In Scala, there are no static variables or methods. Scala uses singleton object, which is essentially class with only one object in the source file.
  • Here you don,t require to mention data type and function return type explicitly. Scala is enough smart to deduce the type of data.
  • In Scala evaluation is lazy by default. Scala evaluates expressions only when they are required.
  • Scala provides a standard library that includes the actor model. So you can write concurrency control.
  • Higher-order functions are the function that either takes a function as an argument or returns a function.

What is Scala Used for?

Scala has the capability to interpolate with the existing Java code and libraries. It is mainly a static type language. There is no concept of primitive type data in Scala. It is a multi-paradigm language that supports multi-core architecture. The main uses of Scala are described below.

Statically Typed language:-

Scala feels dynamic but it is strongly statically language. It provides type interface for variables and functions. A statically typed language avoids the mistake in code and also helps programmers to write proper code and debug code easily. But in dynamic languages, errors are visible only when you run a program.

Example:-

def dup[T](x: T, n: Int): List[T] = {
if (n == 0 ) Nil
else
x :: dup(x, n - 1)
}
println(dup[Int](3, 4))
println(dup("three", 3))

Method dup is parameterized with type T and value parameters x: T and n: Int. Scala type system automatically infers the type of the parameter according to the value.

Built-in Practices And Pattern:-

Scala was developed with the intention of creating new innovations in programming language research to mainstream languages like Java. This language already has some best practices and patterns that are built in the language. It also offers to adopt new languages like Python, Ruby, etc to implement functional programming.

Pattern matching lets check a value against a pattern. You can use this in place of a switch statement or a series of if-else statements in Java.

import scala.util.Random
val x: Int = Random.nextInt(10)
x match
{
case 0 => "zero"
case 1 => "one"
case 2 => "two"
case _ => "many"
}


More Expressive:-

Scala is inherently more expressive than Java. One who learns Scala after Java finds it easier as well as interesting. Let understand it by this example:-

Java code:
Public class wordcount{
Public static void main(String [] args){
StringToken st= new StringToken(args[0]);
Map<String, Integer> map= new HashMap<String, Integer>();
while(st.hasMoreTokens()) {
String word= st.nextToken();
Integer count= map.get(word);
If(count == null)
map.put(word, count+1);
}
System.out.println(map);
}
}
Scala code:
Object WordCountScala extends App {
Println( args(0).split(“ ”).groupBy(x => x).map(t => t._1 -> t._2.length))
}

Multi-paradigm

Scala supports both kinds of programming object-oriented programming as well as functional programming. you can easily explore both sides of functional and OOP together. You are able to define different types associated with both data attributes and behavioral attributes. Scala functions allow you to pass values and also supports anonymous functions.

Inter-Operability:-

The interoperability feature of Java is one of the best options in Scala. This enables Scala developers to use all libraries of Java directly from Scala code. It is also possible to call Scala code from Java and the user can easily write any part of a program in Scala and rest in Java.

Demanding:-

The main use of scala is better growth and job. Scala will help to increase your demand and will make you even more marketable. Many companies like Twitter, LinkedIn, Foursquare, etc are using Scala.

Frameworks:-

Scala provides various libraries that can be used to build many frameworks. There are already many frameworks that have come to existence like Lift and Play. Akka is another Scala-based framework. IT is concurrent and established like a toolkit.

Precise Syntax:-

Scala has a very precise syntax as compared to Java. Java has very long syntax. Scala’s, this feature makes it more readable and concise. ScalaC can generate and work for better code.

Easy To Learn:-

Scala’s object-oriented functionality makes it easy to learn. Scala has clean syntax, nice libraries as well as good online documentation.

Advantage and Disadvantage

  • Highly functional
  • Great for analytics
  • Good IDE support
  • Inherently immutable object
  • Limited community presence
  • Hard to learn
  • Lack of ease of adoption
  • Limited backward compatibility

Scala Frameworks And Libraries

How to write Scala programs

Here I am giving you a small example of how you can write Scala program. Firstly, you need to install Scala on your machine. And you must have to install jdk on your machine because Scala compiler creates .class file which is byte code. Scala interpreter executes this byte code by using jvm.

Example:-

object ScalaExample{  
    def main(args:Array[String]){  
        println "Hello Scala"  
    }  
}  

In the above code, you created an object ScalaExample. It contains a main method and display message using printIn method.

This file is saved with the name ScalaExample.scala.
Command to compile the code is : scalac ScalaExample.scala
Command to execute the compiled code is: scala ScalaExample
After executing code it will give the following output:-

Hello Scala

By using functional approach

def scalaExample{  
    println("Hello Scala")  
}  
scalaExample            // Calling of function

Output

Hello Scala

Versions Of Scala

By now many versions of Scala has been launched. At present Scala 2.13 is in use. Scala 3.0 will release in start of 2020. Features it will contain are:-

  • Scala 3.0 will promote programming idioms.
  • It will be more simplified.
  • It will consolidate language constructs.
  • This will improve consistency, performance, and safety.

Scala Vs Other Languages

Scala has been in a tough fight to overthrow Java. Java has remained one of the most popular, versatile programming languages since the time it was created. Scala was introduced with the intent of addressing many of the concerns developers have with Java.
Where many programming languages trying to compete with Java have failed, Scala has succeeded.
The language, built on top of the JVM, consists:
-Compatibility with Java
-Interoperability

Same as Java, Scala often compared with python. Python and Scala are the two major languages for Data Science, Big Data. Python and Scala both are object-oriented languages.

Let’s go throw some more specific points about Java, Scala, and Python:-

Java

  • Java is a programming language developed by Sun microsystems in 1995.
  • Developers choose Java because it has great libraries, widely used Excellent tooling and a huge amount of documentation available.
  • Some cons of Java are verbosity, NullpointerException, Overcompexity is praised in community culture and bloat.
  • Companies that use Java:-
    Airbnb
    Uber Technologies
    NetFlix
    Spotify
    Instagram
    Pinterest

Scala

  • Scala is an acronym for Scalable language. that means is Scala grows with you.
  • This language provides Static typing, Pattern matching, types. Scala uses Java Virtual Machine for compilation. Overall Scala is a fun language to use.
  • Cons of Scala are slow compilation time, too few developers available, Multiple ropes to hang yourself.
  • Companies that use Scala:-
    Twitter
    Coursera
    9GAG
    Asana
    Groupon
    Reddit

Python

  • Python is a general-purpose programming language, created by Guido Van Rossum.
  • It has great libraries, Readable and beautiful code. In Python development is rapid.
  • Python cons are:- still divided between python 2 and python 3, poor syntax for functions. Package management is a mess.
  • Companies that use Python:-
    Dropbox
    Uber Technologies
    Netflix
    Instagram
    Spotify 

Technologies Written In Scala

  1. Apache Spark
  2. Scalding
  3. Apache Kafka
  4. Finagle
  5. Akka
  6. ADAM
  7. Liches

Future Scope

As mention, Scala has many uses once you learn it, In the future, it will surely increase Scala developer’s value in the market. They will be able to develop new frameworks and use the dynamic feature of this language. Scala being trending largely all over the world.