The reduceRight method in JavaScript uses an accumulator and a value from an array in order to reduce the array.

Examples

Let’s reduce the nested array below into a single array:

const arry = [
    [2, 4],
    [6, 8],
    [10, 12]
];

const reduceArray = arry.reduceRight((acc, curr) => acc.concat(curr));
console.log(reduceArray); //[10, 12, 6, 8, 2, 4];

reduceRight starts at the last array ([10, 12]) and works its way to the first array ([2, 4]).