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
startOptional-
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.lengthis used. - If
start < -buffer.lengthorstartis omitted,0is used. - If
start >= buffer.length, an empty buffer is returned.
- Negative index counts back from the end of the buffer — if
endOptional-
Zero-based index at which to end extraction, converted to an integer.
slice()extracts up to but not includingend.- Negative index counts back from the end of the buffer — if
-buffer.length <= end < 0,end + buffer.lengthis used. - If
end < -buffer.length,0is used. - If
end >= buffer.lengthorendis omitted orundefined,buffer.lengthis used, causing all elements until the end to be extracted. - If
endimplies a position before or at the position thatstartimplies, an empty buffer is returned.
- Negative index counts back from the end of the buffer — if
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® 2026 Language Specification> # sec-sharedarraybuffer.prototype.slice> |
Browser compatibility
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