With over 17.4 million users worldwide, JavaScript established itself as the most commonly used programming language. Thanks to its ease of use, speed, versatility, a wide range of features, and many other factors, JavaScript became the go-to language to build web applications.
But despite all its advantages, building a scalable application using JavaScript is no easy feat. To do so, you’ll need to make certain design choices, follow several principles, but more importantly, choose the right framework for your project.
What is a JavaScript Framework?
In programming, a framework is a set of components used to create the building blocks and outlines of software. In other words, it’s a tool that provides customizable solutions in order to speed up the development process.
In contrast to a simple library, a framework isn’t highly specialized and is constrained to a certain work environment. As such, it may contain several libraries, each specialized in a particular field. The concept of a framework is based on the principle of inversion of control (IoC), a design feature in which the framework calls on custom-written pieces of code when needed.
A JavaScript framework is a collection of JavaScript code libraries that supply developers with pre-written code for use in a JavaScript runtime environment. Many JavaScript frameworks are available on the market tailored to suit different purposes, such as building applications, developing websites, configuring servers, or creating video games.
What Makes an Application Scalable?
In order to create an application that’ll be able to handle an increasing number of users over time without compromising performance, there are a number of core design principles that need to be implemented. Here are a few of them:
- Horizontal scaling: Horizontal scaling is often preferred to vertical scaling as it allows for a more cost-efficient, flexible, and hassle-free implementation. This method is also virtually limitless. As the needs grow, the company can add more instances to share the processing and memory workload across devices.
- Maintenance and automation-friendly design: Scalability requires day-to-day monitoring and regular updates. Hence, the application must be designed for easy updating and maintenance to ensure optimal performance.
- Even work distribution: To prevent bottlenecks from hurting the scalability of the app, it’s mandatory to distribute work as evenly as possible while cutting down on the core workload.
- Asynchronous architecture: The asynchronous method facilitates client-server communication by delivering continuously updated data to the user. An asynchronous architecture helps build more scalable applications as it allows software engineers to handle all tasks in progress at the same time.
- Statelessness processing: Applications that aspire to be scalable should always aim for statelessness. A stateless app is incredibly fault-tolerant because its components can be easily redistributed in the event of a breakdown. They also can be quickly scaled to adapt to changes in load.
Top 5 JavaScript Frameworks for Building Scalable Applications
- Node.js
Originally created by Ryan Dahl in 2009, Node.js is an asynchronous event-driven back-end JavaScript runtime built on Google’s V8 JavaScript engine, which can run on most operating systems. Influenced by systems such as Ruby’s EventMachine and Python’s Twisted, Node.js operates on a single-thread event loop, allowing the framework to manage thousands of concurrent connections on a single process.
Over the years, Node.js has become one of the most popular JavaScript frameworks because of its numerous advantages: ease of use, community support, cost-effectiveness, high performance, short loading time… and great scalability.
When it comes to scaling, the framework is very efficient at handling a large volume of operations as long as they’re not too computation-heavy. Because it’s event-driven and single-threaded by design, Node.js shines at developing fast, efficient, and scalable web applications.
However, it's worth noting that while Node.js is efficient for handling I/O-bound operations, it may not be suitable for CPU-intensive tasks due to its single-threaded nature.
Features:
- Highly-scalable
- Cross-platform compatibility
- Asynchronous and non-blocking
- AngularJS
Launched in 2010 by Google, AngularJS is a free, open-source JavaScript framework designed for developing single-page applications. It was conceived with the intent to simplify the development and testing of web apps thanks to its Model-View-Controller architecture (MVC) specifically tailored for dynamic applications.
Being one of the oldest front-end frameworks on the market, Google decided to stop supporting it in January 2022. But this didn’t mark the end of AngularJS. As the framework is still one of the most used Javascript frameworks on the market, it still receives a lot of support from the community and 3rd party corporations.
Thanks to its modular development structure, Angular is designed to build large-scale projects that can easily sustain a sudden increase in users. Its vast library and various frameworks help make both mobile and web applications faster, more flexible, and more scalable.
However, AngularJS has been succeeded by Angular (also known as Angular 2+), which is a complete rewrite of the framework.
Features:
- Two way data-binding
- Extensive library
- Very testable
- Ember.js
Introduced in 2011, Ember.js is an open-source JavaScript framework that aims to make web development more productive and enjoyable for software engineers. To this end, it includes a router, view layer, and data management library, covering the entire development process.
Despite being around for over a decade, Ember is still a top-notch JavaScript framework with a massive user base, including big corporations such as Microsoft, Netflix, and LinkedIn. However, Ember.js isn’t the most beginner-friendly as it has a big learning curve in comparison to other frameworks like React.
With its many features and conventions, Ember provides an optimal environment for building complex and high-scale applications. The framework allows developers to build scalable single-page web apps easily thanks to its built-in idioms, best practices, and patterns.
However, it should be noted that Ember.js has its own learning curve and may have a smaller user base than other frameworks like React or Angular.
Features:
- Data models
- Convention over configuration
- Built-in debugging tools
- React.js
React.js, more commonly referred to as React, is a front-end JavaScript library developed by Facebook (now Meta) with the goal of facilitating the process of creating single-page applications. React focuses solely on app UX. Hence it can be used in addition to another library or framework such as AngularJS.
Although React.js isn’t a framework per se, it’s so widely used for front-end development that we had to include it in this list. According to the StackOverflow 2022 Developer Survey, React is the second most popular framework after Node.js, and part of its success lies in its scalability.
Thanks to the modular architecture of the framework, React apps are easy to scale. Its components can be conveniently extracted, merged, and reused, while its nature makes for trouble-free maintenance.
However, it's worth mentioning that React is primarily a view library and not a full-fledged framework, although it can be combined with other libraries or frameworks to build complete applications.
Features:
- One-way data binding
- Virtual DOM
- Unidirectional data flow
- Meteor.js
First released in 2011 under the name Skybreak, Meteor.js, also known as Meteor, is an open-source isomorphic JavaScript framework written using Node.js. The framework has the advantage of supporting several programming paradigms. It also comes with a vast number of libraries specifically tailored for everyday tasks.
Meteor.js’ popularity lies in its features that make it easy to develop real-time web applications while maintaining high flexibility and scalability at each step of the process. In addition, Meteor is very beginner-friendly, as it requires a low amount of code to develop applications, and it can be used with other frameworks such as ReactJS and AngularJS.
The framework provides easy horizontal scalability through the possibility of running various copies behind a load balancer.
However, it could be noted that the popularity of Meteor.js has decreased in recent years, and developers may prefer other frameworks for specific use cases.
Features:
- Real-time applications by default
- Easy to convert web apps into mobile apps
- Rapid prototyping
The magic formula for a scalable JavaScript application
Selecting the most suitable framework for your project is only part of the equation. To build an efficiently scalable application, you must complement your framework with the right library. Many choose to integrate React for the many reasons mentioned above, but there are close to a hundred libraries to pick out from depending on your needs and preferences.
Finally, even with the optimal framework, you’ll need to come up with a solid plan. Prior to conceiving the app, you’ll want to assess your scaling needs, define potential challenges, and select the right tools and metrics to monitor the app’s scalability. All this while making sure that you correctly implement the aforementioned core design principles.