Lodash _.mapKeys() Method

Lodash _.mapKeys() method is used to create an object with the same values as the object and the keys created by running each of the object’s own enumerable string keys.

Syntax:

_.mapKeys(object, iteratee);

Parameters:

• object: This parameter holds the object to iterate over.
• iteratee: It is the function that is invoked per iteration.

Return Value:

This method returns the new mapped object.

Example 1: In this example, we are adding the key and value by the use of the function that is passing into the lodash _.mapKeys() method and print the result in the console.

Javascript

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

// Using the _.mapKeys() method
console.log(
    _.mapKeys({ 'cpp': 15, 'java': 40, 'python': 63 },
        function (value, key) {
            return key + value;
        }
    ));

Output:

{'cpp15': 15, 'java40': 40, 'python63': 63}

Example 2: In this example, we are returning the age by the use of the function that is passing into the lodash _.mapKeys() method and print the result in the console.

Javascript

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

// The source object
let info = {
    'GFG': { 'user': 'amit', 'age': 23 },
    'codechef': { 'user': 'priya', 'age': 21 }
};

// Using the _.mapKeys() method
console.log(_.mapKeys(info,
    function (o) { return o.age; })
);

Output:

{21: {'age': 21, 'user': "priya"}, 23: {'age': 23, 'user': "amit"}}