Interview Questions.

Top 100+ Ecmascript 6 Interview Questions And Answers

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Top 100+ Ecmascript 6 Interview Questions And Answers

Question 1. What Is Es6?

Answer :

Es6 or ECMASCRIPT 2015 is sixth main launch of ECMAScript language which comes with loads of recent features and syntax for writing net programs in javascript. As presently, not all browsers support ES6, they assist pre-variations of ES6.SO to put in writing web programs in ES6 with a purpose to support all Browsers we wanted gear like Babel and Webpack.

Question 2. List Some New Features Of Es6?

Answer :

New Features in ES6:

Support for constants (additionally called “immutable variables”)
Block-Scope assist for each variables, constants, capabilities
Arrow Functions
Extended Parameter Handling
Template Literals
Extended Literals
Enhanced Regular Expression
Enhanced Object Properties
Destructuring Assignment
Modules, Classes, Iterators, Generators
Support for Map/Set & Weak Map/Weak Set
Promises, Meta-Programming, Internationalization & Localization.
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Question 3. What Is Babel?

Answer :

Babel is the one of the maximum famous javascript transpiler and turns into the enterprise standard. It permits us to jot down ES6 code and convert it again in pre-Es6 javascript that browser helps.

For example look the underneath code snippet.

In ES6 (ECMASCRIPT 2015)

const PI = three.141593;

PI > 3.0;

export PI;

In ES5 after conversion

"use strict";

Object.DefineProperty (exports, "__esModule", 

  Value: real

);

var PI = three.141593;

PI > 3.0;

exports. I = PI;

Question 4. List Steps To Install Babel?

Answer :

Installation

In order to put in Babel, you require node.Js and NPM. Make certain Node.Js is installed for your server.

To take a look at node hooked up or now not run under instructions for your terminal.

Node -v

npm -v

Installing Babel

We can set up Babel CLI regionally by using running under command on terminal.

Npm installation --save-dev babel-cli

Shell Scripting Tutorial
Question five. What Is Webpack?

Answer :

Webpack will let you run an environment that hosts babel.Webpack is open source javascript module bundler which takes modules with dependencies and generates static belongings representing those modules.

Java Script Interview Questions
Question 6. List Benefits Of Using Webpack?

Answer :

Benefits of the use of Webpack:

It bundles your more than one modules and packs it right into a unmarried .Js file.
It comes with included dev server. A small specific app for neighborhood development.You without a doubt consist of one Javascript tag pointed to the server, like localhost:8080/property/package.Js, and get live code updating and asset management totally free.
Question 7. Explain Constants In Es6?

Answer :

Constants are also known as immutable variables are a unique form of variables whose content isn't changed. In Es6 a steady is described the use of const keyword. Constants in Es6 allow protection to overwrite a variable cost, enhance overall performance and helps programmers to put in writing readable and cleaner code.

Example:

In Es6

const WEBSITE_URL = "http://www.Abc.Com";

WEBSITE_URL="new url"; // generate an blunders;

console.Log (WEBSITE_URL);

In earlier version of Es6

// and most effective in worldwide context and not in a block scope

Object.DefineProperty(form of global === "item" ? Global : window, "WEBSITE_URL", 

value: "http://www.Abc.Com", enumerable: proper,

writable:     false,

configurable: false

);

console.Log (WEBSITE_URL);

Java Script Tutorial Node.Js Interview Questions
Question eight. What Are Template Literals In Es6?

Answer :

Template literals are the string with embedded code and variables inside. Template literal permits concatenation and interpolation in a great deal more comprehensive and clear in assessment with earlier versions of Ecma script.

Let see an instance of concatenating a string in javascript.

Var a="Hello";

var b="John";

var c = a+ " " + b;

Console.Log(c); //outputs Hello John;

In ES6 concatenation and interpolation is accomplished by using lower back tick “ in a single line. To interpolate a variable virtually installed to  braces forwarded via $ sign.>/p>

// In ES6

allow a="Hello";

let b="John";

permit c=`$a $b`;

console.Log(c); //outputs Hello John;

Question 9. What Is Spread Operator In Es6?

Answer :

Spread Operator offers a brand new manner to control array and gadgets in Es6.A Spread operator is represented by using … observed through the variable name.

Example:

allow a =[7,8,9];

allow b=[1,2,3,...A,10];

console.Log(b); // [1,2,3,7,8,9,10]

So spread operator spreads the contents of variable a and concatenates it in b.

Another Example

function print(...Z)

 console.Log (z);

print(1,2,three,four);//[1,2,3,4]

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Question 10. Explain Destructuring Assignment In Es6?

Answer :

Destructing undertaking in some other improvement in Es6. It allows us to extract records from array and gadgets into separate variables.

Example:

permit complete name =['John','Deo'];

let [first_name,last_name]=complete name;

console.Log (first_name,last_name);

// outputs John Deo

Another instance

let c=[100,200,330,400];

permit [a,...B]=c;

console.Log (a,b);

// outputs 100 [200, 330, 400]

Node.Js Tutorial
Question eleven. How To Create A Javascript Class In Es6?

Answer :

In Es6 you can create a class the usage of the Class key-word. Below is sample javascript elegance in ES6.

Magnificence User

    constructor(name, age) 

        this.Name  = call;

        this. Age = age;

    

   get Data() 

        console.Log(this.Call + " is " + this. Age + " years antique !");

    

var consumer = new User("foo", 7);

s1.GetData();

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