A new method TypedArray.prototype.with(), was introduced in ECMAScript 2023 (ES2023) to provide a means of modifying an element in a particular TypedArray without altering the underlying array directly, it generates a new TypedArray with the required alteration and then returns it.

TypedArray instances with() method copies to changing a value at a particular index through bracket notation, giving back a fresh typed array where the value at the specified index is substituted with the specified one, Array.prototype.with() employs an equivalent procedure.

Syntax

TypedArray.prototype.with(index, value)

Parameter:

• index: (Required) Zero-based index at which to change the typed array, converted to an integer.
• value: (Required) Any value to be assigned to the given index.

Return Type:

A new typed array with the element  index replaced with value.

Example 1: In this example, we are replacing an element.

const numbers = new Int8Array([1, 3, 5, 7, 9]);

const modifiedNumbers = numbers.with(2, 10);

console.log(numbers);    
console.log(modifiedNumbers);

Output:

Int8Array(5) [1, 3, 5, 7, 9]
Int8Array(5) [1, 3, 10, 7, 9]

Example 2: In this example, we are chaining with other methods.

// Red, Green, Blue color values
const colors = new Uint8Array([255, 0, 0, 0, 255, 0]); 

const modifiedColors = colors.with(1, 255).with(5, 255);
// Output: Uint8Array(6) [255, 0, 0, 0, 255, 0]
// (original remains unchanged)

console.log(colors); 
 // Output: Uint8Array(6) [255, 255, 0, 0, 255, 255]
 // (both green and blue set to 255)
console.log(modifiedColors);

Output:

Uint8Array(6) [255, 0, 0, 0, 255, 0]
Uint8Array(6) [255, 255, 0, 0, 255, 255]

Supported Browsers

• Chrome
• Edge
• Firefox
• Opera
• Safari