JavaScript Atomics sub() Method
Last Updated :
22 May, 2023
Among the Atomic Operations, there is a method Atomics.sub() that is used to subtract a given value at a given position in the array and return the old value at that position. No other write operation can happen until the modified value is written back.
Syntax:
Atomics.sub(typedArray, index, value)
Parameters:
- typedarray: It is the shared integer typed array you want to modify.
- index: It is the position in the typedArray from where you want to subtract a value from.
- value : It is the number you want to subtract.
Return Value: Atomics.sub() returns the old value at the given position (typedArray[index]).
Examples of the above function are provided below.
Examples:
Input : arr[0] = 9;
Atomics.sub(arr, 0, 3);
Output : 9
Input : arr[0] = 3;
Atomics.sub(arr, 0, 2);
Output : 3
Examples of the above function are provided below.
Example 1:
javascript
let buf = new SharedArrayBuffer(25);
let arr = new Uint8Array(buf);
arr[0] = 9;
console.log(Atomics.sub(arr, 0, 3));
console.log(Atomics.load(arr, 0));
|
Output :
9
6
Example 2:
javascript
let buf = new SharedArrayBuffer(25);
let arr = new Uint8Array(buf);
arr[0] = 3;
console.log(Atomics.sub(arr, 0, 2));
console.log(Atomics.load(arr, 0));
|
Output:
3
1
Application: Whenever we want to update(subtract) a value at a specified position in a given array and want the older value which was at that position to be returned, we use the Atomics.sub() operation in JavaScript.
Example:
javascript
let mybuffer = new SharedArrayBuffer(25);
let myarray = new Uint8Array(mybuffer);
myarray[0] = 40;
console.log(Atomics.sub(myarray, 0, 20));
console.log(Atomics.load(myarray, 0));
|
Output :
40
20
Exceptions :
- If the typedArray is not one of the allowed integer types then the Atomics.sub() operation throws a TypeError.
- If the typedArray is not a shared typed array then the Atomics.sub() operation throws a TypeError.
- If the index used as an argument to the Atomics.sub() operation is out of the bound in the typedArray then the Atomics.sub() operation throws a RangeError.
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.
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