The static Atomics.exchange()
method stores a given value at a given position in the array and returns the old value at that position. This atomic operation guarantees that no other write happens between the read of the old value and the write of the new value.
The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.
Syntax
Atomics.exchange(typedArray, index, value)
Parameters
typedArray
- An integer typed array. One of
Int8Array
,Uint8Array
,Int16Array
,Uint16Array
,Int32Array
,Uint32Array
,BigInt64Array
, orBigUint64Array
. index
- The position in the
typedArray
to exchange avalue
. value
- The number to exchange.
Return value
The old value at the given position (typedArray[index]
).
Exceptions
- Throws a
TypeError
, iftypedArray
is not one of the allowed integer types. - Throws a
RangeError
, ifindex
is out of bounds in thetypedArray
.
Examples
Using exchange()
const sab = new SharedArrayBuffer(1024); const ta = new Uint8Array(sab); Atomics.exchange(ta, 0, 12); // returns 0, the old value Atomics.load(ta, 0); // 12
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Atomics.exchange' in that specification. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
exchange | Chrome
Full support
68
| Edge
Full support
79
| Firefox
Full support
78
| IE No support No | Opera No support No | Safari No support 10.1 — 11.1 | WebView Android
No support
60 — 63
| Chrome Android
No support
60 — 63
| Firefox Android
Full support
57
| Opera Android No support No | Safari iOS No support 10.3 — 11.3 | Samsung Internet Android
No support
No
| nodejs Full support 8.10.0 |
Legend
- Full support
- Full support
- No support
- No support
- See implementation notes.
- See implementation notes.
- User must explicitly enable this feature.
- User must explicitly enable this feature.