JavaScript Atomics or() Method

Among the Atomic Operations, there is a method Atomics.or() that is used to compute a bitwise OR operation with a given value at a given position in an array. The old value at that position is returned by Atomics.or() function. No other write operation can happen until the modified value is written back.

Syntax:

Atomics.or(typedArray, index, value)

Parameters:

• typedarray: It is the shared integer typed array you want to modify.
• index: It is the position in the typedArray where you want to compute bitwise OR.
• value: It is the number you want to compute the bitwise OR with.

Return Value: Atomics.or() returns the old value at the given position (typedArray[index]).

Examples of the above function are provided below.

Examples: 

Input : arr[0] = 9;
        Atomics.or(arr, 0, 3);
Output : 9

Input : arr[0] = 3; 
        Atomics.or(arr, 0, 2);
Output : 3

Examples of the above function are provided below. 

Example 1:

Javascript

// creating a SharedArrayBuffer
let buf = new SharedArrayBuffer(25);
let arr = new Uint8Array(buf);

// Initialising element at zeroth position of array with 9
arr[0] = 9;

// 9 (1001) OR 3 (0011) = 11 (1011)
// Displaying the return value of the Atomics.or() method
console.log(Atomics.or(arr, 0, 3));

// Displaying the updated SharedArrayBuffer
console.log(Atomics.load(arr, 0));

Output:

9
11

Example 2:

Javascript

// creating a SharedArrayBuffer
let buf = new SharedArrayBuffer(25);
let arr = new Uint8Array(buf);
// Initialising element at zeroth position of array with 3
arr[0] = 3;

// (0011) AND 2 (0010) =  3 (0011)
// Displaying the return value of the Atomics.or() method
console.log(Atomics.or(arr, 0, 2));

// Displaying the updated SharedArrayBuffer
console.log(Atomics.load(arr, 0));

Output:

3
3

Exceptions :

• Throws a TypeError, if typedArray is not one of the allowed integer types.
• Throws a TypeError, if typedArray is not a shared typed array type.
• Throws a RangeError, if the index is out of bounds in the typedArray.

Supported Browser:

• Google Chrome
• Microsoft Edge
• Firefox
• Opera
• Safari

We have a complete list of Javascript Atomic methods, to check those please go through this JavaScript Atomics Complete Reference article.

We have a Cheat Sheet on Javascript where we covered all the important topics of Javascript to check those please go through Javascript Cheat Sheet-A Basic guide to JavaScript.