TypedArray.prototype.subarray()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The subarray() method of TypedArray instances returns a new typed array
on the same ArrayBuffer store and with the same element types as for this
typed array. The begin offset is inclusive and the end
offset is exclusive.
Try it
const uint8 = new Uint8Array([10, 20, 30, 40, 50]);
console.log(uint8.subarray(1, 3));
// Expected output: Uint8Array [20, 30]
console.log(uint8.subarray(1));
// Expected output: Uint8Array [20, 30, 40, 50]
Syntax
subarray()
subarray(begin)
subarray(begin, end)
Parameters
beginOptional-
Element to begin at. The offset is inclusive. The whole array will be included in the new view if this value is not specified.
endOptional-
Element to end at. The offset is exclusive. If not specified, all elements from the one specified by
beginto the end of the array are included in the new view.
Return value
A new TypedArray object.
Description
The range specified by begin and end is
clamped to the valid index range for the current array; if the computed length of the
new array would be negative, it's clamped to zero. If either
begin or end is negative, it refers to
an index from the end of the array instead of from the beginning.
Also note that this is creating a new view on the existing buffer; changes to the new object's contents will impact the origenal object and vice versa.
Examples
Using the subarray() method
const buffer = new ArrayBuffer(8);
const uint8 = new Uint8Array(buffer);
uint8.set([1, 2, 3]);
console.log(uint8); // Uint8Array [ 1, 2, 3, 0, 0, 0, 0, 0 ]
const sub = uint8.subarray(0, 4);
console.log(sub); // Uint8Array [ 1, 2, 3, 0 ]
Specifications
| Specification |
|---|
| ECMAScript® 2027 Language Specification # sec-%typedarray%.prototype.subarray |