Atomics.sub()

BaselineWidely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since December 2021.

TheAtomics.sub() static method subtracts a given valueat a given position in the array and returns the old value at that position. This atomicoperation guarantees that no other write happens until the modified value is writtenback.

Try it

// Create a SharedArrayBuffer with a size in bytesconst buffer = new SharedArrayBuffer(16);const uint8 = new Uint8Array(buffer);uint8[0] = 7;// 7 - 2 = 5console.log(Atomics.sub(uint8, 0, 2));// Expected output: 7console.log(Atomics.load(uint8, 0));// Expected output: 5

Syntax

Atomics.sub(typedArray, index, value)

Parameters

typedArray: An integer typed array. One ofInt8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,BigInt64Array, orBigUint64Array.
index: The position in thetypedArray to subtract avalue from.
value: The number to subtract.

Return value

The old value at the given position(typedArray[index]).

Exceptions

TypeError: Thrown iftypedArray is not one of the allowed integer types.
RangeError: Thrown ifindex is out of bounds in thetypedArray.

Examples

Using sub

const sab = new SharedArrayBuffer(1024);const ta = new Uint8Array(sab);ta[0] = 48;Atomics.sub(ta, 0, 12); // returns 48, the old valueAtomics.load(ta, 0); // 36