What is Lodash?
Lodash is a JavaScript library that provides utility functions for common programming tasks using a functional programming paradigm; it builds upon the older underscore.js library.
Lodash has several built-in utility functions that make coding in JavaScript easier and cleaner. Instead of writing common functions, again and again, the task can be accomplished with a single line of code.
Installation
Lodash can be installed via NPM:
npm install --save lodash
After installation is complete, Lodash can be imported into a JavaScript file as:
import _ from "lodash"
Now, all of Lodash’s functions can be accessed by the underscore operator.
Functions
Some handy functions included in Lodash are:
_.concat()
The _.concat() function simply concatenates values to an existing array, as shown below:
let arr = ['dog', 'cat', 'bird', 'hamster']let arr = _.concat(arr, 'zebra', 'snake');// Output => arr = ['dog', 'cat', 'bird', 'hamster', 'zebra', 'snake']
_.find()
Instead of using a loop to iterate through an array to search for an object, the _.find() function can perform the same task in a single line. Moreover, it can be used to find an object using multiple properties.
let friendlist = [{ firstName: "Jennifer", lastName: "Lawrece", age: 28, gender: "female" },{ firstName: "Brad", lastName: "Pitt", age: 5, gender: "male" },{ firstName: "Quentin", lastName: "Tarantino", age: 54, gender: "male" },{ firstName: "Kate", lastName: "Winslet", age: 40, gender: "female" }];let user = _.find(friendlist, {lastName: "Pitt"});// user -> { firstName: "Brad", lastName: "Pitt", age: 5, gender: "male" }let overFifty = _.find(users, function(user) {return friendlist.age > 50; // return friends who are over 50});// overFifty -> { firstName: "Quentin", lastName: "Tarantino", age: 54, gender: "male" }
_.intersection
The normal code, to find the common elements between two arrays, uses a for loop with several lines of code. In Lodash, this is achieved in a single line with the _.intersection() function:
let arr1 = ["football", "cricket", "tennis", "squash"]let arr2 = ["cricket", "rugby", "badminton", "tennis"]let commonElements = _.intersection(arr1, arr2);// commonElements-> ["cricket", "tennis"]
More functions and information on Lodash can be found in the official documentation.
Free Resources
