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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.

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Syntax

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.

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 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