Introduction
Node.js has one of the largest ecosystems of open source libraries with over 1.3 million packages published on npm. This massive selection allows developers to quickly build projects without reinventing the wheel.
But it can be overwhelming to find the most useful npm packages amongst thousands of options. In this guide, we’ll explore the top 10 npm packages that should be in every Node.js developer’s toolkit along with practical examples.
Whether you’re just getting started with Node.js or are looking to expand your skills, knowing these core packages will boost your productivity and capabilities. Let’s dive in!
Top 10 npm Packages
1. Express
The Express framework provides a robust set of features for building web and mobile apps in Node. With minimal boilerplate code, Express makes it easy to set up routes, integrate middlewares, handle requests/responses, and render dynamic views.
Express is the de facto standard for most Node.js applications. Its simple yet flexible API allows creating a diverse range of apps from REST APIs to full-stack sites.
// Minimal Express app
const express = require('express');
const app = express();
app.get('/', (req, res) => {
res.send('Hello World');
});
app.listen(3000);In just a few lines of code, we have a fully functioning Express server able to handle requests and responses. The wide range of hooks and customization options makes Express a must-have for any Node developer.
2. Async
JavaScript’s asynchronous nature makes managing async code complex. The Async library abstracts away much of this complexity through utility functions like parallel execution, queues, and flow control.
For example, limiting parallel async tasks:
const async = require('async');
async.parallelLimit([
callback => {
// Task 1
},
callback => {
// Task 2
}
], 2, callback);Async takes care of executing the tasks concurrently up to the parallel limit. The callback is fired when everything completes.
This makes asynchronous code easier to write and maintain. Async should be a standard part of any Node.js developer’s toolkit.
3. Lodash
JavaScript lacks many common utilities found in other languages. Lodash fills this gap by providing over 100 functions for working with arrays, objects, strings, numbers and more.
For instance, deep flattening arrays:
const _ = require('lodash');
const nested = [1, [2, [3]]];
_.flattenDeep(nested);
// [1, 2, 3]Chaining, sorting, filtering – Lodash makes mundane data tasks trivial. It’s essential for boosting everyday JavaScript programming.
4. Nodemon
Having to manually restart your server during development can be tedious. Nodemon solves this by automatically restarting when it detects changes:
nodemon index.jsNow your app will reload whenever you modify source files. Nodemon saves tons of valuable time during the development process.
5. PM2
In production, PM2 manages and runs your Node app with features like monitoring, zero-downtime reloads, and built-in load balancing.
To run your app with PM2:
pm2 start index.jsIt will be kept alive forever, load balanced across all cores, and monitored against crashes. PM2 is a must-have for taking your Node apps to production.
6. Dotenv
Hardcoding configuration like database passwords and API keys into source is a bad idea. Dotenv allows loading secrets from a .env file:
// .env
DB_PASSWORD=secret// index.js
require('dotenv').config()
// DB password loaded into process.env
const pwd = process.env.DB_PASSWORD;This keeps sensitive data out of source control and configures apps based on the environment. Dotenv is essential for managing configurations cleanly.
7. Axios
Making HTTP requests is a common need in most applications. Axios is a promise-based library that simplifies requests:
const axios = require('axios');
axios.get('https://api.example.com/users')
.then(res => {
// Response handlers
})
.catch(err => {
// Request error
});Axios supports all HTTP verbs, response handling, and request/response transformation. Its clean interface abstracts away the underlying complexity.
8. Webpack
Bundling modules and assets by hand can become unmanageable. Webpack streamlines the process with a robust plugin ecosystem and intuitive configuration:
// webpack.config.js
module.exports = {
entry: './src/index.js',
output: {
filename: 'bundle.js'
},
module: {
// Loader configs
}
};Webpack handles bundling JavaScript, CSS, images, fonts and more out of the box. The plugin system allows endless customization and optimizing bundles.
9. Jest
Serious applications require testing. Jest is the most popular test framework for JavaScript applications with its easy API, built-in assertions, mocks, and code coverage reports.
// Hello.test.js
const Hello = require('./Hello');
test('says hello', () => {
expect(Hello('John')).toEqual('Hello John');
});Jest integrates beautifully into any Node.js or frontend project for comprehensive unit and integration testing.
10. ESLint
Linting catches bugs, enforces style rules, and improves code quality. ESLint is the leading JavaScript linter that integrates directly into most editors for real-time feedback:
// .eslintrc.json
{
"rules": {
// Rules
}
}ESLint will save you countless hours by eliminating entire classes of errors, bugs, and anti-patterns.
Key Takeaways
These 10 packages form an essential toolkit that every Node.js developer should know. They provide solutions for app building, tooling, productivity, deployment, and more across the ecosystem.
Beyond this list, make sure to explore npm for specialized packages tailored to your needs. The Node.js community releases innovative tools daily to push the limits of what JavaScript can accomplish.
Mastering both the core utilities and niche packages will take your Node.js development to the next level. The immense flexibility and constant growth is what makes the Node ecosystem so exciting to work with!
Frequently Asked Questions
Here are some common questions about essential Node.js packages:
Q: Is Express required for Node.js web apps?
A: No it’s not strictly required. But it provides useful features like routing, middlewares, error handling that you would otherwise need to build yourself.
Q: What’s the difference between Nodemon and PM2?
A: Nodemon is for development auto-restarting on file changes. PM2 is for production deployment with monitoring, clustering etc.
Q: Should I use webpack or parcel for bundling?
A: Both are good. Webpack is more configurable while parcel optimizes for zero-config out of the box usage. Evaluate both to see which fits your needs.
Q: Is Lodash still useful with modern JavaScript features?
A: Absolutely. While new APIs like map/filter/reduce help, Lodash provides many utilities not covered by vanilla JavaScript like deep cloning, flattening, etc.
Q: Can ESLint replace JSHint or JSLint?
A: Yes, ESLint can completely replace those older linting options. It has more rules, better editor integration, and more flexibility through plugins.