es6-plus-features.md

ES6+ Features

ES6 stands for ECMA Script Standards 6 / ES6 / ES 2015. The following features were approved by the ECMA International / ECMA technical committee in the year 2015 and is called ES6 because it is the sixth release of features / rules.

Arrow Functions ES6

Single Line Functions

Destructuring

Destructuring Object - 1

let myObj = {
    name : "John Doe",
    dob : " 13012004",
    height: 176,
    weight : 79,
    eyes : "brown"}

// Destructuring the object 
let {name, dob, height, weight, eyes} = myObj;
console.log(name) // John Doe
console.log(eyes) // brown

Destructuring Object - 2 Spread syntax (...)

let myObj = {
    name : "John Doe",
    dob : " 13012004",
    height: 176,
    weight : 79,
    eyes **: "brown"}
let {name, dob, ...rest} = myObj;
console.log(name) //John Doe
console.log(rest) /*{height: 176,
                     weight : 79,
                     eyes: "brown"} */

Array Destructuring

Object Destructuring

What happens to Overlapping keys ?

Exporting

There are basically two export statements

export

// filename : heading.js
export const heading = "This is my heading";

If we export just using the export statement then at the time of import the variable name should match and we must keep the variable in {} to import it as an object.

// filename : index.js
import {heading} from './heading';

export default

// filename : heading.js
const heading = "This is my heading";
export default heading;

If we use the default export statement then at the time of import we can have our own variable i.e. the export variable need not be the same as import variable

// filename : index.js
import newHeading from './heading';

Short Circuit Evaluation

||

const firstValue = '' || 'myName'; // myName

If the first value is falsy then the second value is returned. If the first value is truthy then the first value is returned

&&

const firstName = 'myName' && 'myNickName'; // myNickName

If the any of the value is falsy then nothing will be returned. if both the values are truthy then the second value is returned.