Atomics.or()
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.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.
Try it
Syntax
Atomics.or(typedArray, index, value)
Parameters
typedArray
-
An integer typed array. One of
Int8Array
,Uint8Array
,Int16Array
,Uint16Array
,Int32Array
,Uint32Array
,BigInt64Array
, orBigUint64Array
. 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 thetypedArray
.
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.
5 0101 1 0001 ---- 5 0101
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
BCD tables only load in the browser