Atomics.xor()

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 Atomics.xor() static method computes a bitwise XOR 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.

Syntax

Atomics.xor(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 XOR.

value

The number to compute the bitwise XOR 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 XOR operation yields 1, if a and b are different. The truth table for the XOR operation is:

a b a ^ b

0	0	0
0	1	1
1	0	1
1	1	0

For example, a bitwise XOR of 5 ^ 1 results in 0100 which is 4 in decimal.

5 0101 1 0001 ---- 4 0100

Examples

Note that these examples cannot be run directly from the console or an arbitrary web page, because SharedArrayBuffer is not defined unless its security requirements are met.

Using Atomics.xor()

js
// Create a SharedArrayBuffer with a size in bytes
const sab = new SharedArrayBuffer(1024);
// Create a view and set the value of the 0 index
const ta = new Uint8Array(sab);
ta[0] = 7;

// 7 (0111) XOR 2 (0010) = 5 (0101)
console.log(Atomics.xor(ta, 0, 2)); // 7, the old value
console.log(Atomics.load(ta, 0)); // 5, the new/current value