The Atomics.and() static
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, or BigUint64Array.
index- : The position in the
typedArrayto compute the bitwise AND.
- : The position in the
value- : The number to compute the bitwise AND with.
Return value
The old value at the given position
(typedArray[index]).
Exceptions
- TypeError
- : Thrown if
typedArrayis not one of the allowed integer types.
- : Thrown if
- RangeError
- : Thrown if
indexis out of bounds in thetypedArray.
- : Thrown if
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