The static Atomics
.or()
method computes a bitwise OR with 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 until the modified value is written back.
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.or(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 compute the bitwise OR. value
- The number to compute the bitwise OR with.
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
.
Description
The bitwise OR operation yields 1, if either a
or b
are 1. The truth table for the OR operation is:
a |
b |
a | b |
---|---|---|
0 | 0 | 0 |
0 | 1 | 1 |
1 | 0 | 1 |
1 | 1 | 1 |
For example, a bitwise OR of 5 & 1
results in 0101
which is 5 in decimal.
5 0101 1 0001 ---- 5 0101
Examples
Using or
const sab = new SharedArrayBuffer(1024); const ta = new Uint8Array(sab); ta[0] = 2; Atomics.or(ta, 0, 1); // returns 2, the old value Atomics.load(ta, 0); // 3
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Atomics.or' 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 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
or | 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.