TypedArray.prototype.fill()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2016.
The fill() method of TypedArray instances changes all elements within a range of indices in a typed array to a static value. It returns the modified typed array. This method has the same algorithm as Array.prototype.fill().
Try it
const uint8 = new Uint8Array([0, 0, 0, 0]);
// Value, start position, end position
uint8.fill(4, 1, 3);
console.log(uint8);
// Expected output: Uint8Array [0, 4, 4, 0]
Syntax
fill(value)
fill(value, start)
fill(value, start, end)
Parameters
value-
Value to fill the typed array with.
startOptional-
Zero-based index at which to start filling, converted to an integer.
endOptional-
Zero-based index at which to end filling, converted to an integer.
fill()fills up to but not includingend.
Return value
The modified typed array, filled with value.
Description
See Array.prototype.fill() for more details. This method is not generic and can only be called on typed array instances.
Examples
Using fill()
new Uint8Array([1, 2, 3]).fill(4); // Uint8Array [4, 4, 4]
new Uint8Array([1, 2, 3]).fill(4, 1); // Uint8Array [1, 4, 4]
new Uint8Array([1, 2, 3]).fill(4, 1, 2); // Uint8Array [1, 4, 3]
new Uint8Array([1, 2, 3]).fill(4, 1, 1); // Uint8Array [1, 2, 3]
new Uint8Array([1, 2, 3]).fill(4, -3, -2); // Uint8Array [4, 2, 3]
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-%typedarray%.prototype.fill |
Browser compatibility
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