Atomics.and()
The static Atomics.and()
method computes a bitwise AND 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.and(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 compute the bitwise AND. value-
The number to compute the bitwise AND with.
Return value
The old value at the given position
(typedArray[index]).
Exceptions
-
Throws a
TypeError, iftypedArrayis not one of the allowed integer types. -
Throws a
RangeError, ifindexis out of bounds in thetypedArray.
Description
The bitwise AND operation only yields 1, if both a and b are
1. The truth table for the AND operation is:
a |
b |
a & b |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
For example, a bitwise AND of 5 & 1 results in 0001 which
is 1 in decimal.
5 0101 1 0001 ---- 1 0001
Examples
Using and()
const sab = new SharedArrayBuffer(1024);
const ta = new Uint8Array(sab);
ta[0] = 5;
Atomics.and(ta, 0, 1); // returns 5, the old value
Atomics.load(ta, 0); // 1
Specifications
| Specification |
|---|
| ECMAScript Language Specification # sec-atomics.and |
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