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JavaScript Array reduceRight()


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


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:
Argument Description
total Required. The initialValue, or the previously returned value of the function
currentValue Required. The value of the current element
currentIndex Optional. The array index of the current element
arr Optional. The array object the current element belongs to
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


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 »

Related Pages

Array Tutorial

Array Const

Array Methods

Sorting Arrays

Array Iterations