`Array.prototype.with()`

Returns a new array with the element at a given index replaced, without mutating the original.

Since ES2023 Spec ↗

Syntax

arr.with(index, value)

Name	Type	Required	Description
`index`	`number`	Yes	Index of the element to replace. Negative counts from the end.
`value`	`any`	Yes	The new value to place at the index.

Array — A new array with the element replaced.

const a = [1, 2, 3];
console.log(a.with(1, 9), a);

Output

[ 1, 9, 3 ] [ 1, 2, 3 ]

console.log([1, 2, 3].with(-1, 0));

Output

[ 1, 2, 0 ]

Non-mutating counterpart to bracket assignment. Throws RangeError for an out-of-bounds index (unlike `arr[i] = v`). Always returns a new array.