New Features in JavaScript 2023
| Feature | Description |
|---|---|
| #! (Shebang) | Tells the operating system which interpreter to use to execute the script |
New Array Features in 2023
| Feature | Description |
|---|---|
| findLast() | Returns the value of the last element that satisfies a condition |
| findLastIndex() | Returns the index of the last element that satisfies a condition |
| toReversed() | Reverses an array without altering the original array |
| toSorted() | Sorts an array without altering the original array |
| toSpliced() | Splices an array without altering the original array |
| with() | Updates array elements without altering the original array |
Browser Support
ECMAScript 2023 is supported in all modern browsers since July 2023 :
| Chrome 110 | Edge 110 | Firefox 115 | Safari 16.4 | Opera 96 |
|---|---|---|---|---|
| Feb 2023 | Feb 2023 | Jul 2023 | Mar 2023 | May 2023 |
JavaScript Array findLast() Method
ES2023 added the findLast() method that will start from the end of an array and return the value of the first element that satisfies a condition.
Example
const temp = [27, 28, 30, 40, 42, 35, 30];
let high = temp.findLast(x => x > 40);JavaScript Array findLastIndex() Method
The findLastIndex() method finds the index of the last element that satisfies a condition.
Example
const temp = [27, 28, 30, 40, 42, 35, 30];
let pos = temp.findLastIndex(x => x > 40);JavaScript Array toReversed() Method
ES2023 added the Array toReversed() method as a safe way to reverse an array without altering the original array.
The difference between the new toReversed() method and the old reverse() method is that the new method creates a new array, keeping the original array unchanged, while the old method altered the original array.
Example
const months = ["Jan", "Feb", "Mar", "Apr"];
const reversed = months.toReversed();JavaScript Array toSorted() Method
ES2023 added the Array toSorted() method as a safe way to sort an array without altering the original array.
The difference between the new toSorted() method and the old sort() method is that the new method creates a new array, keeping the original array unchanged, while the old method altered the original array.
Example
const months = ["Jan", "Feb", "Mar", "Apr"];
const sorted = months.toSorted();JavaScript Array toSpliced() Method
ES2023 added the Array toSpliced() method as a safe way to splice an array without altering the original array.
The difference between the new toSpliced() method and the old splice() method is that the new method creates a new array, keeping the original array unchanged, while the old method altered the original array.
Example
const months = ["Jan", "Feb", "Mar", "Apr"];
const spliced = months.toSpliced(0, 1);JavaScript Array with() Method
ES2023 added the Array with() method as a safe way to update elements in an array without altering the original array.
Example
const months = ["Januar", "Februar", "Mar", "April"];
const new = months.with(2, "March");#! JavaScript Shebang
In operating systems, a shebang (also known as hashbang, pound-bang, sharp-exclamation or hash-pling) is a sequence of two characters: a number sign (#) and an exclamation mark (!).
#! at the beginning of a script tells the operating system what interpreter should be used to execute the script:
Example
#!
/usr/bin/env nodeThe example above tells the operating system to use the node program to run the script.
Now, you can run JavaScript code with ./fileName.js instead of node fileName.js .