JavaScript Array reduceRight()
Example
Subtract the numbers in the array, starting from the end:
const numbers = [175, 50, 25];
document.getElementById("demo").innerHTML
= numbers.reduceRight(myFunc);
function myFunc(total, num) {
return total - num;
}
Try it Yourself »
More "Try it Yourself" examples below.
Definition and Usage
The reduceRight() method executes a reducer function for each value of an array
, from right to left.
reduceRight() returns a single value which is the function's accumulated result.
reduceRight() does not execute the function for empty array elements.
Browser Support
reduceRight() is fully supported in all modern browsers:
| Chrome 3 | IE 9 | Edge 12 | Firefox 3 | Safari 5 | Opera 10.5 |
| Jun 2009 | Sep 2010 | Jul 2015 | Jan 2009 | Jun 2010 | Mar 2010 |
Syntax
array.reduceRight(function(total, currentValue, currentIndex, arr), initialValue)
Parameter Values
| Parameter | Description | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| function(total, currentValue, index, arr) | Required. A function to be run for each element in the array. Function arguments:
|
||||||||||
| initialValue | Optional. A value to be passed to the function as the initial value |
Technical Details
| Return Value: | Returns the accumulated result from the last call of the callback function |
|---|---|
| JavaScript Version: | ECMAScript 5 |
More Examples
Example
Subtract the numbers, right-to-left, and display the sum:
const numbers = [2, 45, 30, 100];
document.getElementById("demo").innerHTML = numbers.reduceRight(getSum);
function getSum(total, num) {
return total - num;
}
Try it Yourself »
