There has never been a better time to be a JavaScript developer.

Not only is there a multitude of frameworks, libraries, and tools available to developers, it's evident that the popularity of web applications is going to grow for a long time.

Add to this the fact that many JavaScript frameworks allow you to build native apps, and it is easy to see why it has become the go-to language for so many developers.

We truly are spoiled for choice with the number of sophisticated frameworks out there, which can make it somewhat difficult to choose one for your project.

In this article, I'll cover the 10 most important JavaScript libraries (with the best listed at the end) to help you make a more informed decision.

Table of Contents

You can skip to a specific section of this article on the best JavaScript libraries and frameworks using the table of contents below:

• 1. Vue.js
• 2. Svelte
• 3. Angular
• 4. Ember.js
• 5. Meteor
• 6. Polymer
• 7. Backbone.js
• 8. Aurelia
• 9. React.js
• 10. Node.js
• Conclusion

1. Vue.js

Vue is dubbed as a "progressive framework for building user interfaces". Progressive means that the framework is incrementally adoptable - you can integrate as much, or as little, of it as you want in your projects.

At 20kb when minified, Vue is lightweight but powerful enough to leverage as a full-featured framework when used with some supporting libraries.

If you're wondering how Vue compares with other frameworks, their documentation includes comparisons with other popular options. While it was written by the Vue core team, it is rather unbiased and objective.

They lay out where they believe Vue has advantages over other frameworks, and where you may not need those advantages (e.g. when you don't need full control and flexibility over some aspects of the framework and just want to start coding ASAP).

2. Svelte

Svelte is a component framework similar to Vue, but it is different from the rest in terms of how the code is executed.

Traditional frameworks follow a declarative paradigm where the web browser needs to do extra work to process the declarative structures into DOM (document object model) operations. This carries with it performance costs on the client side.

Svelte differs in that it runs at build time and converts components into much more efficient imperative code that updates the DOM. The result is improved performance of your web application.

The latest version of Svelte has focused on improving the developer's experience when working with the framework. A major focus on version 3 has been to reduce the amount of code you have to write to get the results you need.

You can find more information about the Svelte "write less code" paradigm in this blog post, where you can see a function written in React (discussed later), Vue, and Svelte.

As you'll see, what takes 442 characters of code in React and 263 characters in Vue, can be achieved in only 145 characters in Svelte!

3. Angular

Angular is a robust framework developed by Google that can handle all your web application needs, from prototype to large-scale deployments.

With it, you can build high-performance apps for web, mobile, native mobile, and even native desktop platforms.

As you can imagine, a framework built by Google is bound to have a rich set of tools and features to help you develop your project.

These include:

• Unit testing
• Command-line tools
• Code generation
• Intelligent code completion
• Instant errors
• UI Templates
• An animations API

Angular is supported by most modern IDEs, which makes it incredibly easy to start working with it. You can even try it out without installing it on your machine. Just go to their getting started page to create the ready-made sample project in StackBlitz.

4. Ember.js

Ember.js is a framework based on the model–view–viewmodel (MVVM) pattern that allows you to build single-page web applications.

It packs a considerable punch, too, which explains why many prominent companies leverage its capabilities. Some of these include Netflix, Intercom, Microsoft, Apple Music, Square, Groupon, LinkedIn, Vine, Twitch, and Chipotle.

Ember's data layer, called Ember Data, is a fully featured data access library that allows you to access data across multiple sources at once, setup asynchronous relationships, and keep models up-to-date across your web application with great flexibility.

The built-in URL router is also particularly powerful. It allows you to load data asynchronously with dynamic URL segments and query parameters, and has support for nested URLs with incremental data fetching, nested loading, and error substates.

Another useful feature is Ember's test harness, which is built into your app by default. The test harness automatically generates tests for every entity that is generated in the application.

The great thing about the Ember tests is that they also run in the browser, so you can run component or acceptance tests to verify everything is working as expected.

5. Meteor

Meteor is a full-stack platform for web and mobile applications. It differs from some of the frameworks I cover here in that it contains both the front-end and the back-end components you need to build your apps.

Meteor was written using Node.js (covered later) and allows for rapid prototyping of code that can be deployed on Android, iOS, and the web. Native apps are compiled through Apache Cordova, which means you can maintain one codebase for both Android and iOS. This saves you a lot of time and money.

The cool part is you can integrate it with pretty much any front-end JavaScript framework, such as Vue, React, Svelte, or Angular. And with more than 14,000 packages deployed, Meteor's rich ecosystem, forums, and documentation has all the support and resources you'll need when creating your next web application.

6. Polymer

Polymer is maintained by the front-end engineers in the Google Chrome team. It is a set of libraries that you can use to enhance your web apps.

One of the key aspects of Polymer is Web Components, a set of modern web standards that allow you to extend HTML. These include all kinds of useful elements and tools such as data grids, date pickers, carousels, media players, and many others.

With Web Components developers can create and share custom elements that can work on any site, integrate with many frameworks, and inter-operate with the web browser's built-in elements.

You can build your application entirely out of Web Components or you may simply choose the elements you need to get the job done. And if you're feeling adventurous, you can even create your own custom elements for your project.

7. Backbone.js

Based on the model–view–presenter (MVP) pattern, Backbone.js is a lightweight library with a RESTful JSON interface that you can use to build single-page web applications.

The MVP paradigm allows you to represent your data with the models, which keeps business logic separate from the user interface of your application.

Data can be created, validated, and stored server-side. When a UI action causes an attribute of a model to change, Backbone notifies all corresponding views of the change so they may respond accordingly.

This is done by the model by keeping an internal table of data attributes and change events when any of its data is modified. The models also handle syncing the data with the persistence layer, most often using a REST API with a backing database.

As you can imagine, this paradigm greatly reduces the burden on you to write code that manages changes to the views based on user actions, allowing you more time to work on your back-end logic or building better user interfaces.

8. Aurelia

Aurelia is a high-performance framework that prides itself on being extremely easy to learn - if you know HTML and JavaScript, there is little else for you to learn to build even the most complex apps.

By using what is known as "reactive binding", Aurelia knows exactly what changes and when it changes. This allows updates to your UI to be done in the most efficient way possible.

The Aurelia core team have developed numerous plugins for state management, internationalization, validation, and other common tasks.

In addition, the framework is highly extensible. You can create your own custom elements, add custom attributes to existing elements, control template generation, customize template syntax, create new reactive binding types, and a bunch of other cool stuff.

When it comes to testing your code, Aurelia has most bases covered. Their powerful Dependency Injection Container and testing library make it quick and easy to write integration tests, so that you can build mainability and longevity into your codebase.

9. React.js

React.js is a popular framework for building user interfaces that is maintained by Facebook and some other individual contributors. You can use it to build single-page or mobile applications.

Judging by Facebook and Instagram's performance and scalability, we can certainly see how powerful this framework is for building fast web apps.

React's declarative design makes it easy to create interactive UIs that dynamically update as data changes. Declarative views also make the code more predictable and easier to debug.

While controllers and models are not supported in React, you'll find that components play a central role. Components allow you to split the UI into independent, reusable pieces that you can manipulate as you need.

You can think of them as similar to JavaScript functions - they can accept inputs, called props, and return elements that describe what should be rendered on the screen.

With React, you can build encapsulated components that can manage their own state. By writing the component logic in JavaScript instead of templates, you're able to pass rich data through your app whilst keeping state out of the DOM, thus reducing maintenance nightmares.

React also features a virtual DOM, which works by creating an in-memory data-structure cache that computes differences after operations before updating the browser's DOM. This allows you to write your code as if the entire page is rendered on each change, with the advantage that the React libraries only update the parts of the DOM that have changed after the operation.

Of course, React also integrates well with external plugins, libraries, and frameworks, so you can extend it to your heart's content.

10. Node.js

Last, but certainly not least, we have Node.js - a cross-platform JavaScript runtime environment that can be used to build scalable applications.

Node.js allows you to build server-side functionality for your applications using JavaScript and various modules that can be used to access the file system, for networking (DNS, HTTP, TCP, TLS/SSL, or UDP), cryptography functions, data streams, and other essential functions.

The neat thing about Node.js function execution is that functions are non-blocking. This means that commands can execute in parallel or concurrently, whereas in PHP, for example, most functions block each other so each one must wait for the previous one to finish before it can begin executing.

Most modern IDEs support Node.js integrations, and this allows you to use the platform in your current setup with minimal hassle. Node.js' package manager, npm, makes it extremely simple to install, update, and remove packages in your projects and you have access to thousands of open-source libraries to use in your project.

When you're ready to deploy your application, you'll find great support on most major hosting platforms including Amazon Web Services, Google Cloud Platform, Joyent, and Jetlastic.

Conclusion

In this article, I covered the 10 most important JavaScript libraries for 2020 (and beyond). We looked at mature frameworks, used by large multinational organizations, as well as some relatively newer up-and-comers.

As you can see, the level of sophistication in the tools available to us is unprecedented. It truly is a treat to be a JavaScript developer in 2020.

As always, happy coding!