ES7 and ES8 features

String.prototype.padStart/padEnd

padStart and padEnd allow us to pad a given string with any text of our choice to ensure a string matches a given length:

// padStart(desiredLength, textToPrepend)
Examples:-
'abc'.padStart(12, 'Hi') // 'HiHiHiHiHabc'
// Only use what gets to length
'9894'.padStart(9, '6363') // '636369894'
// padEnd(desiredLength, textToAppend)
Examples:-
'99'.padEnd(9, '01') // '990101010'
''.padEnd(9, '01') // '010101010'

Exponentiation

JavaScript has introduced a shorthand method of exponentiation:

// 2 to the power of 10
Math.pow(2, 10) // 1024
// ..becomes
2 ** 10 // 1024

It will reduce the size of the code.

Object.entries

Object.entries allows us to get an object's enumerable property pairs in an array format ([key, value]):

// Object literal
Object.entries({ 'A': 'a', 'B': 'b' }); // [["A","a"],["B","b"]]
// String
Object.entries('VIKAS') // [["0","V"],["1","I"],["2","K"],["3","A"],["4","S"]]

Object.entriesfollows the same order as work in for loop etc.

Object.values

Object.values allow us to convert an object into an array:

// Object literal
Object.values({ 'z': 11, 'y': 17 }) // [11, 17] 
//let store in some variable
abc = Object.values({ 'z': 11, 'y': 17 })
Array.isArray(abc) //true
// Array-like object (order not preserved)
Object.values({ 90: 'ninety', 990: "abc", 1: 'yes' }) // ['yes','ninety','abc']
// String
Object.values('kohli') // ["k", "o", "h", "l", "i"]
// Array
Object.values([6, 7, 8, 9, 2, 3]) // [6,7,8,9,2,3]

Object.values provides value entries in object literals, arrays, strings, etc.

Array.prototype.includes

Array.prototype.includes is somewhat similar like indexOf but instead of returning its index, this returns a boolean value (true or false)

['v', 'i', 'k', 'a', 's'].includes('s') // true --> not index
['v', 'i', 'k'].includes('l') // false --> not index

Trailing Commas

let myObj = { ba:'fdfdfdb', db: 'fddfcfd', } // No error in JS as well!
let myArr = [1, 2, 3, ] // No error in JS as well!
[6, 7, 8, 9,].length // 4
[9, 8, 7, , , , , , , , ].length // 10

As in many languages, this feature is already there like Python and many more.

Also, I saw David Walsh post for the same, you can also visit his link

Six Tiny But Awesome ES7 + ES8 Features