The reduceRight() method runs a function on each array element to produce (reduce it to) a single value.
The reduceRight() works from right-to-left in the array. See also reduce().
The reduceRight() method does not reduce the original array.
This example finds the sum of all numbers in an array:
Example
const numbers = [45, 4, 9, 16, 25];
let sum = numbers1.reduceRight(myFunction);
function myFunction(total, value, index, array) {
return total + value;
}
let sum = numbers1.reduceRight(myFunction);
function myFunction(total, value, index, array) {
return total + value;
}
Note that the function takes 4 arguments:
- The total (the initial value / previously returned value)
- The item value
- The item index
- The array itself
The example above does not use the index and array parameters. It can be rewritten to:
Example
const numbers = [45, 4, 9, 16, 25];
let sum = numbers1.reduceRight(myFunction);
function myFunction(total, value) {
return total + value;
}
let sum = numbers1.reduceRight(myFunction);
function myFunction(total, value) {
return total + value;
}
Array.reduceRight() is supported in all browsers except Internet Explorer 8 or earlier. Practice Excercise Practice now