JavaScript has been around for 20+ years, and it's one of those languages that never stop evolving. The language has been experiencing a fast-paced growth recently that makes me wonder whether the modern front-end JavaScript technologies that are well known today will be relevant a couple of years later. 

Nevertheless, it's important to be ahead of the game by working with the latest tools and frameworks for a better development workflow. This article explores various JavaScript libraries, frameworks, and tools that you should consider learning right now.

Here's a quick index of the libraries and frameworks in this post:

Frameworks

• React
• Vue
• Ember.js
• Angular
• Next.js
• Svelte
• Ionic
• Gatsby
• Meteor.js
• Express

Libraries

• jQuery
• Chart.js
• Three.js
• D3
• Anime.js

Task Runners

• Gulp
• ESLint
• Babel
• Grunt
• Webpack

Testing

• Jest
• Jasmine
• Mocha

Introduction

The JavaScript environment has grown huge. It has its own ecosystem of libraries, frameworks, tools, package managers, and new languages that compile down to JavaScript. Interestingly, npm, which is the de facto package manager for JavaScript, is also the largest software registry in the world. Here is an excerpt from a post published on Linux.com back in January 2017.

At over 350,000 packages, the npm registry contains more than double the next most populated package registry (which is the Apache Maven repository). In fact, it is currently the largest package registry in the world.

Only eight months later, there were about 500,000 packages in the npm registry. That's a massive growth compared to other package repositories. 

As a front-end JavaScript developer, it's important to keep up with the modern JavaScript tools and libraries. When a technology becomes popular, demand for it is high, which in turn means more coding jobs that pay the highest salary in the industry. So I've assembled a list of the popular JavaScript technologies that I think you should be aware of. 

Frameworks

A framework has an architecture that dictates the flow of control in your application. The framework describes the skeleton and tells you how everything should be organized. The basic functionality required to get the application up and running is also provided to you. Moreover, you are bound to follow the framework's design principles and patterns. The difference between a framework and a library is that you call a library, whereas the framework calls you. 

A framework often comprises many libraries and has a higher level of abstraction. Functionality such as event handling, making AJAX calls, template and data binding, and testing are built into the framework.  

React

React is a JavaScript library built by the developers of Facebook and Instagram. React is consistently voted as one of the most-loved and most-popular technologies among developers.

So why is React getting all the attention? With React, it is possible to create an interactive UI using a declarative approach where you can control the state of the application by saying "the view should look like this". It uses a component-based model where the components are reusable UI elements, and each component has its own state.

React uses a Virtual DOM so that you don't have to be concerned about directly manipulating the DOM. Other notable features of React include one-way data flow, optional JSX syntax, and a command-line tool for creating a React project with zero build configuration. 

Angular

Angular was once the most popular JavaScript technology among front-end developers. It is still very widely used and is backed by Google and a community of individuals and corporations. 

Some of the features of Angular include:

• TypeScript over JavaScript as the default language
• component-based architecture
• improved performance on both mobile and web platforms
• better tooling and scaffolding options

Vue.js

The Vue.js framework has been trending for several years. It is also the most popular JavaScript framework on GitHub in terms of the GitHub star count. Vue claims to be a less opinionated framework and thus easy for developers to catch up with. Vue's HTML-based template syntax binds the rendered DOM to the instance data. 

The framework offers a React-like experience with its Virtual DOM and reusable components that you can use to create both widgets and entire web applications. Moreover, you can use the JSX syntax to write the render functions directly.  When the state changes, Vue.js uses a reactivity system to determine what has changed and rerenders the minimal number of components. Vue.js also supports the integration of other libraries into the framework without much hassle.

Next.js

Calling itself "The React Framework for Production", Next.js is a React-based framework that adds new functionality, including server-side rendering and static website generation. React is a JavaScript package that's often used to create web applications that are rendered using JavaScript in the client's browser. It provides you with the finest developer experience possible, as well as all of the functionality you'll need for production.

Ember.js

Ember.js is a Javascript framework that helps developers to build scalable single-page web applications by leveraging language, best practices, and patterns from existing single-page-app ecosystem patterns. It enables the development of client-side JavaScript applications by providing a comprehensive solution that includes data management and an application flow.

Svelte

Whereas traditional frameworks such as React and Vue do the majority of their work in the browser, Svelte moves that work into a compile step that occurs when you build your app. This makes it a useful option for user interface development.

Ionic

Ionic is a free and open-source framework that provides a library of mobile-optimized UI components, gestures, and tools for creating high-speed, high-interactivity apps. It allows you to create a hybrid mobile application.

Gatsby

This open-source static website generator uses Webpack and GraphQL technology and is built on the React front-end development framework. You can use Gatsby to create progressive web apps, as well as static sites that are fast and secure. It's used by several well-known organizations, including Tinder, Snapchat, and Affirm, and it's very fast and flexible when building websites.

Meteor.js

Meteor.js is a free JavaScript framework for developing web and mobile applications. Meteor is convenient and popular, and it has a reactive UI. If you are an experienced developer, then you should try Meteor.js. It has a fast and convenient development process.

Meteor is especially geared to writing full-stack apps with a shared codebase for the client and server.

Express

Express is a popular and powerful tool for writing the server-side code for any web application. It is both free and open-source. It is used to quickly and easily design and create web apps.

Libraries

A library is a reusable piece of code that offers certain functionality. It is a collection of functions, objects, and classes that you can use in your application. A library abstracts different layers so that you don't have to be concerned about their implementation details. 

You can call a library function and pass it some parameters, and the library executes it and returns the control back to you. However, it doesn't place any structural constraints that restrict how you use the library. Popular JavaScript libraries include:

jQuery

jQuery is a library that made JavaScript more approachable and DOM manipulation easier than before. jQuery's gentle learning curve and easy syntax gave rise to a generation of new client-side developers. A few years back, jQuery was considered a solid solution for building robust websites with cross-browser support. jQuery's core features such as DOM manipulation based on CSS selectors, event handling, and making AJAX calls fueled its popularity. 

However, things have changed, and the JavaScript environment has steadily evolved. Some of jQuery's features have been incorporated into the newer ECMAScript specification. Moreover, the new libraries and frameworks in use today have a native way of binding the DOM, and hence plain DOM manipulation techniques are not required anymore. jQuery's popularity is on the decline, but I don't see it disappearing anytime soon.

D3: Data-Driven Documents

D3 (or D3.js) is a powerful JavaScript library for producing interactive visualizations using web standards such as SVG, HTML, and CSS. Unlike other visualization libraries, D3 offers better control over the final visual result. 

D3 works by binding the data to the DOM and then making the transformation to the document. It also has an ecosystem of its own, which consists of plugins and libraries that extend its basic functionality. The library has been around since 2011, and it has tons of documentation and tutorials that can help you get started. 

Chart.js

This beautiful JavaScript library was built to enable developers and designers to easily visualize data using JavaScript. Chart.js is one of the most widely used data visualization packages, as well as one of the most user-friendly. With minimal code, Chart.js creates ready-to-use interactive visuals for your data.

Anime.js

With the simple but powerful Anime.js animation library, you can create a broad range of animations on your CSS properties, as well as SVG images and DOM attributes. You can read more about Anime.js here.

Three.js

Three.js is a JavaScript library for creating and animating three-dimensional computer images in a web browser. It's a single JavaScript file that incorporates effects, settings, cameras, lights, materials, models, shaders, animations, and 3D objects, among other things.

Tools

A tool is a collection of routines that help you in the development process. Unlike a library, a tool usually executes a task on the client code. It takes your code as input, performs a task on it, and then returns an output. The commonly used tools include transpilers and build tools, asset minifiers, module bundlers, and scaffolding tools. 

General-Purpose Task Runners

General-purpose task runners are the tools used to automate certain repetitive tasks. The popular general-purpose task runners include:

Gulp

Gulp is a JavaScript toolkit used as a task runner and as a build system in web development. Repetitive tasks like compilation, code minification, image optimization, unit testing, and linting should be automated. Gulp makes the process of writing tasks easier, even for people who are less familiar with JavaScript. 

Gulp uses pipelines to stream the data from one plugin to another, and the final result is outputted to a destination folder. Gulp performs better compared to Grunt because it doesn't create temporary files for storing intermediate results, which results in fewer I/O calls.

Grunt

The Grunt task runner and automation tool has a command-line interface that lets you run custom tasks defined in a file called a Gruntfile. Grunt has thousands of plugins to choose from, which should cover most of the common repetitive tasks that you'd encounter. With Grunt, you can run all the tasks under a single command, making your life easier.

npm

Gulp and Grunt require you to spend time learning and mastering a new tool, which takes time. Introducing additional dependencies into your project can be avoided by choosing an alternative that is already bundled with Node.js. Although npm is better known as a package manager, npm scripts can be used to perform the bulk of the abovementioned tasks. 

ESLint

ESLint is a pluggable JavaScript tool that can analyze your code to find issues that can lead to bugs or inconsistencies in your code.

Prettier

Prettier is a code formatter with strong opinions. It enforces a consistent style by analyzing your code and reprinting it according to its standards, which take into consideration the maximum line length and wrap code as needed. It works with a variety of languages and can be integrated with some of your favorite editors.

Webpack

With the Webpack module bundler, you can bundle JavaScript files for use in browsers, and Webpack can also modify and bundle your styles and assets.

Babel

Babel is a free and open-source JavaScript compiler that converts new language features to older ones. It's also known as a "transpiler". Anyone can write code that uses all the modern JavaScript features but runs on older browsers without using Babel if you just use the bundler. 

Testing Tools

Testing is the process of validating and verifying that the application meets the expected business and technical requirements. The Test-Driven Development approach also aids in discovering bugs and therefore should be treated as an integral part of the modern front-end development stack.

Jest

Jest is a relatively new testing framework authored by Facebook and has been well-received by the React community. There is a common misconception that Jest is specifically designed to work with React; however, according to the Jest Documentation:

Although Jest may be considered React-specific test runner, in fact it is a universal testing platform, with the ability to adapt to any JavaScript library or framework. You can use Jest to test any JavaScript code.

The biggest advantage of using Jest over other test suites is that you require zero or minimal configuration to start writing tests. The framework has a built-in assertion library and supports the use of mock functions or spies.

Jest has a feature called snapshot testing that lets you ensure that the UI of the application doesn't change unexpectedly. The developers at Facebook and other contributors have been pouring a lot of work into this project recently, so it wouldn't be a surprise if Jest turns out to be the most popular testing framework for JavaScript in the years to come.

Mocha

This JavaScript testing framework features browser support, async support including promises, test coverage reports, and a JavaScript API for running tests. Mocha is often paired with an assertion library such as Chai, should.js, expect.js, or better-assert because it lacks an assertion library of its own.

Jasmine

Jasmine is a behavior-driven testing framework for JavaScript. Jasmine aims to be a browser, platform, and framework-independent test suite. Jasmine has its own assertion library called matchers that gives it a clean and easy-to-read syntax. Jasmine doesn't have a built-in test runner, and you might have to use a generic test runner like Karma instead. 

Summary

JavaScript, the language of the web, has stayed relevant since the days of its inception back in 1995. It will probably stay that way as long as browsers don't decide to ditch it for another language. Although there are a lot of other languages that compile down to JavaScript, there is no other scripting language that will replace JavaScript in the foreseeable future. Why? Because JavaScript has grown too popular to be replaced.

The JavaScript environment is definitely evolving, which is evident from the current trends in web development. Older libraries and frameworks have been replaced with new technologies. The new generation of front-end libraries, frameworks, and tools are gaining ground and getting universal acceptance. 

This post has been updated with contributions from Ezekiel Lawson. Ezekiel is a front-end developer who focuses on writing clean, maintainable code with web technologies like JavaScript, Vue.js, HTML, and CSS.