The Javascript arr.reduceRight() method in JavaScript is used to convert elements of the given array from right to left to a single value.
Syntax:
array.reduceRight( function(total, currentValue, currentIndex, arr), initialValue )
Parameter: This method accepts five parameters as mentioned above and described below:
- function(total, currentValue, index, arr): It is the required parameter and is used to run for each element of the array. It contains four parameters which are listed below:
- total: It is a required parameter and used to specify the initialValue or the previously returned value of the function.
- currentValue: It is a required parameter and is used to specify the value of the current element.
- currentIndex: It is an optional parameter and is used to specify the array index of the current element.
- arr: It is an optional parameter and is used to specify the array object the current element belongs to.
- initialValue: It is an optional parameter and is used to specify the value to be passed to the function as the initial value.
Below are examples of the Array reduceRight() method.
Example 1: In this example, we will be using the reduce() method to find the difference between the elements of the array.
Javascript
let arr = [175, 50, 25];function subofArray(total, num) { return total - num;}function myGeeks(item) { console.log(arr.reduceRight(subofArray));}myGeeks() |
-200
Example 2: This example uses reduceRight() method to return the difference of all array elements from the right.
Javascript
let arr = [10, 20, 30, 40, 50, 60];function subofArray(total, num) { return total - num;}function myGeeks(item) { console.log(arr.reduceRight(subofArray));}myGeeks(); |
-90
Example 3: This example use reduceRight() method to return the round sum of all array elements. The code performs a sum that does not affect by the reduceRight() method.
Javascript
let arr = [1.5, 20.3, 11.1, 40.7];function sumofArray(sum, num) { return sum + Math.round(num);}function myGeeks(item) { console.log(arr.reduceRight(sumofArray, 0));}myGeeks(); |
74
We have a complete list of Javascript Array methods, to check those please go through this Javascript Array Complete reference article.
Supported Browsers: The browsers supported by the JavaScript Array reduceRight() method are listed below:
- Google Chrome 3
- Microsoft Edge 12
- Mozilla Firefox 3.0
- Safari 5
- Opera 10.5
- Internet Explorer 9
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.
