Lodash _.flatMap() Method

Lodash _.flatMap() method creates a flattened array of values by running each element in the collection through iteratee and flattening the mapped results.

Syntax:

_.flatMap(collection, iteratee);

Parameters:

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

Return Value:

This method returns the new flattened array.

Example 1: In this example, we are passing a duplicate function to the lodash _.flatMap() method and an array and getting the result in the console.

javascript

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

// Original array
let user1 = ([35, 47, 58, 69, 94, 13, 72]);

// Use of _.flatMap() method
let gfg1 = _.flatMap(user1, function duplicate(n) {
    return [n, n];
})

// Printing the output
console.log(gfg1);

Output:

[
  35, 35, 47, 47, 58, 58, 
  69, 69, 94, 94, 13, 13,
  72, 72
]

Example 2: In this example, we are passing a duplicate function to the lodash _.flatMap() method and an array and getting the result in the console.

javascript

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

// Original array
let user1 = ([3.5, 4.7, 5.8, 6.9, 9.4, 1.3, 7.2]);
let user2 = ([3, 4, 5, 9, 9, 1, 7]);

// Use of _.flatMap() method
let gfg1 = _.flatMap(user1, function duplicate(n) {
    return [n, n];
})

let gfg2 = _.flatMap(user2, function duplicate(n) {
    return [n, n];
})

// Printing the output
console.log(gfg1);
console.log(gfg2);

Output:

[
  3.5, 3.5, 4.7, 4.7, 5.8, 5.8, 
  6.9, 6.9, 9.4, 9.4, 1.3, 1.3,
  7.2, 7.2
]
[
  3, 3, 4, 4, 5, 5,
  9, 9, 9, 9, 1, 1,
  7, 7
]

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