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Atomics.or()

The Atomics.or() static 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.

Try it

Syntax

js 
Atomics.or(typedArray, index, value)

Parameters

typedArray

An integer typed array. One of Int8Array, Uint8Array, Int16Array, Uint16Array, Int32Array, Uint32Array, BigInt64Array, or BigUint64Array.

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

TypeError

Thrown if typedArray is not one of the allowed integer types.

RangeError

Thrown if index is out of bounds in the typedArray.

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

js 
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 Language Specification
# sec-atomics.or

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet WebView Android Deno Node.js
or 68 79 78 55 15.2 89 79 63 15.2 15.0 89 1.0 8.10.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/or