Lodash _.reduceRight() Method

Lodash _.reduceRight() method is similar to _.reduce() method except that it iterates over elements of collection from right to left.

Syntax:

_.reduceRight(collection, iteratee, accumulator)

Parameters:

This method accepts three parameters as mentioned above and described below:

• collection: This parameter holds the collection to iterate over.
• iteratee: This parameter holds the function invoked per iteration.
• accumulator: This parameter holds the initial value.

Return Value:

This method returns the accumulated value.

Example 1: This code uses the Lodash library to flatten a nested array by iterating from right to left and concatenating subarrays using the _.reduceRight() method.

Here, const _ = require(‘lodash’) is used to import the lodash library in the file.

javascript

// Requiring the lodash library
const _ = require("lodash");

// Original array
var array = [[10, 11], [12, 13], [14, 15]];

// Use of _.reduceRight() method

let gfg = _.reduceRight(array,
    function(flattened, other) {
  return flattened.concat(other);
}, []);

// Printing the output
console.log(gfg);

Output:

[ 14, 15, 12, 13, 10, 11 ]

Example 2: In this example, the code requires the Lodash library and uses the _.reduceRight method to flatten a nested array and then displays the flattened result in the console.

javascript

// Requiring the lodash library
const _ = require("lodash");

// Original array
let array = [['C++', 'C#'],
    ['DAA', 'Java'], ['Lodash', 'Python']];

// Use of _.reduceRight() method

let gfg = _.reduceRight(array,
    function(flattened, other) {
  return flattened.concat(other);
}, []);

// Printing the output
console.log(gfg);

Output:

[ 'Lodash', 'Python', 'DAA', 'Java', 'C++', 'C#' ]

Note:

This code will not work in normal JavaScript because it requires the library lodash to be installed.