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.
The Atomics.sub() static method subtracts 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
// Create a SharedArrayBuffer with a size in bytes
const buffer = new SharedArrayBuffer(16);
const uint8 = new Uint8Array(buffer);
uint8[0] = 7;
// 7 - 2 = 5
console.log(Atomics.sub(uint8, 0, 2));
// Expected output: 7
console.log(Atomics.load(uint8, 0));
// Expected output: 5
Syntax
Atomics.sub(typedArray, index, value)
Parameters
typedArray-
An integer typed array. One of
Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,BigInt64Array, orBigUint64Array. index-
The position in the
typedArrayto subtract avaluefrom. value-
The number to subtract.
Return value
The old value at the given position
(typedArray[index]).
Exceptions
TypeError-
Thrown if
typedArrayis not one of the allowed integer types. RangeError-
Thrown 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 value
Atomics.load(ta, 0); // 36
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-atomics.sub |