SharedArrayBuffer.prototype.slice()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since December 2021.

The slice() method of SharedArrayBuffer instances returns a new SharedArrayBuffer whose contents are a copy of this SharedArrayBuffer'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.

Try it

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

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

console.log(sliced);
// Expected output: Int32Array [42, 0]

Syntax

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

Parameters

start Optional

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

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, 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 SharedArrayBuffer containing the extracted elements.

Examples

Using slice()

js
const sab = new SharedArrayBuffer(1024);
sab.slice(); // SharedArrayBuffer { byteLength: 1024 }
sab.slice(2); // SharedArrayBuffer { byteLength: 1022 }
sab.slice(-2); // SharedArrayBuffer { byteLength: 2 }
sab.slice(0, 1); // SharedArrayBuffer { byteLength: 1 }

Specifications

Specification
ECMAScript® 2025 Language Specification
# sec-sharedarraybuffer.prototype.slice

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
slice

Legend

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Full support
Full support
No support
No support

See also