ECMAScript 2021 (JS 2021/2022)

JavaScript in 2021/2022 continues to evolve, with ES2021/ES2022 bringing enhanced features like private class fields, promise improvements, and record data structures, boosting developer productivity and code quality.

JavaScript New Features in ES2021

JavaScript in 2022 new features :

We will explore all the above methods along with their basic implementation with the help of examples.

Method 1: Promise any()

Promise.any() is a JavaScript ES2021/ES2022 method that takes an array of Promises and returns the first resolved Promise, rejecting only if all Promises reject.

Syntax:

Promise.any(iter)

Example: This example, shows the basic use of Promise.any() method.

let prom1 = new Promise((resolve, reject) => {
    reject("Failure");
})
let prom2 = new Promise((resolve, reject) => {
    reject("Failed to load");
})
let prom3 = new Promise((resolve, reject) => {
    resolve("Worked");
})
let prom4 = new Promise((resolve, reject) => {
    resolve("Successful");
})

let prom = [prom1, prom2, prom3, prom4];

Promise.any(prom).then((val) => { console.log(val) });

Worked

Method 2: String replaceAll()

String replaceAll() is a JavaScript method (ES2021/ES2022) replacing all occurrences of a substring with another, returning a new string.

Syntax:

const newString = originalString.replaceAll(regexp | substr , newSubstr | function)

Example: Below is an example of the String replaceAll() Method.

function gfg() {
    let string = "Geeks or Geeks";
    newString = string.replaceAll("or", "for");
    console.log(newString);
}
gfg();

Geeks for Geeks

Method 3: Numeric Separators (_)

Numeric Separators (_) in JavaScript (ES2021/ES2022) allow improved readability by placing underscores as visual separators in large numbers for better code comprehension.

Syntax:

let num1 = 1_000_000_000;

Example: Here is the basic example of above method.

let num1 = 1_000_000_000;
let num2 = 1000000000;
console.log(num1 === num2);

true

Method 4: Array at()

The JavaScript Array at() method takes an integer value (index) as a parameter and returns the element of that index. It allows positive and negative integers. For the negative integer, it counts back from the last element in the array.

Syntax:

at(index);

Example: This code shows the value extracted at the given index.

const arr = [45, 32, 69, 21];
const index = 3;

console.log(arr.at(index));

21

Method 5: String at()

String.at() finds character at specified index, supports positive and negative indexes. Positive indexes start from array start, negative from end.

Syntax:

let a = str.at(ind);

Example: In this example, we will use the String.at() method with a positive index.

let str1 = "Welcome to GeeksforGeeks";
let str2 = "GeeksforGeeks";
console.log(str1.at(3));
console.log(str2.at(8))

c
G

Method 6: RegExp \D

The RegExp \D Metacharacter in JavaScript is used to search non-digit characters i.e all the characters except digits. It is the same as [^0-9].

Syntax:

/\D/ 

Example: This example searches the non-digit characters in the whole string.

function geek() {
    let str1 = "GeeksforGeeks@_123_$";
    let regex4 = /\D/g;
    let match4 = str1.match(regex4);

    console.log("Found " + match4.length
        + " matches: " + match4);
}
geek()

Found 17 matches: G,e,e,k,s,f,o,r,G,e,e,k,s,@,_,_,$

Method 7: Object.hasOwn()

Object.hasOwn() is a method that checks if an object has a specific property directly on itself, returning true if found, else false.

Syntax:

Object.hasOwn(obj, prop)

Example: This example uses the hasOwn() method to check if a property exists or not.

let details = {
    name: "Raj",
    course: "DSA",
    website: "geeksforgeeks.org",
}

console.log(Object.hasOwn(details, 'name'));
console.log(Object.hasOwn(details, 'course'));
console.log(Object.hasOwn(details, 'phone number'));

true
true
false

Supported browser:

• Chrome 1
• Edge 12
• Firefox 1
• Safari 1
• Opera 3