files/en-us/web/javascript/reference/global_objects/arraybuffer/slice/index.md

metadata

title: ArrayBuffer.prototype.slice()
short-title: slice()
slug: Web/JavaScript/Reference/Global_Objects/ArrayBuffer/slice
page-type: javascript-instance-method
browser-compat: javascript.builtins.ArrayBuffer.slice
sidebar: jsref

The slice() method of {{jsxref("ArrayBuffer")}} instances returns a new ArrayBuffer whose contents are a copy of this ArrayBuffer's bytes from start, inclusive, up to end, exclusive. If either start or end is negative, it refers to an index from the end of the array, as opposed to from the beginning.

{{InteractiveExample("JavaScript Demo: ArrayBuffer.prototype.slice()")}}

// Create an ArrayBuffer with a size in bytes
const buffer = new ArrayBuffer(16);
const int32View = new Int32Array(buffer);
// Produces Int32Array [0, 0, 0, 0]

int32View[1] = 42;
const sliced = new Int32Array(buffer.slice(4, 12));
// Produces Int32Array [42, 0]

console.log(sliced[0]);
// Expected output: 42

Syntax

slice()
slice(start)
slice(start, end)

Parameters

• start {{optional_inline}}
  • : Zero-based index at which to start extraction, converted to an integer.
    • Negative index counts back from the end of the buffer — if -buffer.length <= start < 0, start + buffer.length is used.
    • If start < -buffer.length or start is omitted, 0 is used.
    • If start >= buffer.length, an empty buffer is returned.
• end {{optional_inline}}
  • : Zero-based index at which to end extraction, converted to an integer. slice() extracts up to but not including end.
    • Negative index counts back from the end of the buffer — if -buffer.length <= end < 0, end + buffer.length is used.
    • If end < -buffer.length, 0 is used.
    • If end >= buffer.length or end is omitted is undefined, buffer.length is used, causing all elements until the end to be extracted.
    • If end implies a position before or at the position that start implies, an empty buffer is returned.

Return value

A new {{jsxref("ArrayBuffer")}} containing the extracted elements. It is not resizable, even if the original was.

Examples

Copying an ArrayBuffer

const buf1 = new ArrayBuffer(8);
const buf2 = buf1.slice(0);

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{jsxref("ArrayBuffer")}}
• {{jsxref("SharedArrayBuffer.prototype.slice()")}}