Atomics.sub()
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.
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: 5Syntax
Atomics.sub(typedArray, index, value)Parameters
typedArrayAn integer typed array. One of
Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,BigInt64Array, orBigUint64Array.indexThe position in the
typedArrayto subtract avaluefrom.valueThe number to subtract.
Return value
The old value at the given position(typedArray[index]).
Exceptions
TypeErrorThrown if
typedArrayis not one of the allowed integer types.RangeErrorThrown if
indexis 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); // 36Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-atomics.sub |