WebAssembly (WASM) is a low-level binary instruction format that runs in a sandboxed environment in the web browser. It provides a way to write code in languages other than JavaScript and compile it into the WASM format, which can be executed directly in the browser without a JavaScript interpreter. WASM was introduced to address the limitations of JavaScript and to enable more efficient and performant web applications. However, despite its advantages, WASM cannot replace JavaScript completely. In this blog, we will explore why.

Its early stages

While WebAssembly (WASM) has shown a lot of potential, it is still a relatively new technology that has yet to be widely adopted. While it has gained some traction in recent years, it is likely to take some time before WASM reaches the level of adoption and support that JavaScript currently has. This is partly due to the fact that WASM is still being developed and refined, and there are ongoing efforts to improve its performance, security, and tooling.

One of the key advantages of JavaScript is its access to a wide range of browser APIs that enable developers to build rich and interactive web applications. However, WASM has limited access to browser APIs, which can limit its capabilities in certain use cases. While there are efforts underway to improve WASM's access to browser APIs, it may take some time before it can match the capabilities of JavaScript in this regard.

Performance benefits may not always be significant

While WASM can provide significant performance benefits in certain use cases, such as heavy computation, it may not always be significantly faster than JavaScript for other use cases. In some cases, the overhead of bridging between WASM and JavaScript may negate any performance benefits. This means that developers need to carefully consider whether WASM is the right choice for their particular use case.

Use Cases

WASM is best suited for use cases that require heavy computational work, such as video or audio processing, 3D rendering, scientific simulations, or gaming. It can also be used for developing libraries or modules that need to be integrated with JavaScript code. On the other hand, JavaScript is more suitable for building web applications and user interfaces, as it provides rich APIs and tools for web development, including DOM manipulation, event handling, and asynchronous programming.

Interoperability

WASM and JavaScript are not directly interoperable, which means that they cannot call each other's functions directly. To use WASM with JavaScript, you need to provide a glue layer in JavaScript that exposes the WASM functions as JavaScript functions. This adds an additional layer of complexity to the code and can result in performance overhead. On the other hand, JavaScript code can be easily called from WASM code using the WebAssembly.instantiate() method, which creates a bridge between JavaScript and WASM.

Developer's Perspective

JavaScript has a vast and mature ecosystem, with a rich set of libraries, frameworks, and tools for web development. WASM, on the other hand, is a relatively new technology with limited tooling and support. While some languages such as Rust have excellent tooling for compiling to WASM, developers need to learn new tools and techniques to work with WASM. Additionally, debugging WASM code can be challenging due to its low-level nature and lack of tooling.

Well developed ecosystem

JavaScript has a large and active community of developers, as well as a wide range of libraries, frameworks, and tools for web development. This strong ecosystem can make it easier and faster to develop web applications using JavaScript compared to other technologies. Overall, while WASM has potential, it is unlikely to completely replace JavaScript anytime soon.

TypeScript

TypeScript is a superset of JavaScript that provides static typing and other features to improve developer productivity and code quality. TypeScript can be used to write code that targets both JavaScript and WASM. However, TypeScript's support for WASM is limited, and some language features such as memory management are not fully supported. This can result in additional complexity and workarounds when working with TypeScript and WASM.

Next.js 13 and Turbo Pack

Next.js 13 is a popular web framework built on top of React and Node.js. It provides a file-system-based router and other features to simplify web development. Turbo Pack is an incremental bundler optimized for JavaScript and TypeScript, written in Rust, and built into Next.js 13. Turbo Pack updates 700x faster than Webpack on large applications. Next.js 13 provides an integrated TypeScript experience, including zero-configuration set up and built-in types for Pages, APIs, and more. The Next.js Compiler, written in Rust using SWC, allows Next.js to transform and minify your JavaScript code for production. This replaces Babel for individual files and Terser for minifying output bundles. However, these tools do not support WASM natively, and developers need to use additional tools or techniques to work with WASM code.

Vite

Vite is a fast and lean build tool for modern web projects that provides a dev server and a build command. It comes with sensible defaults and is highly extensible via its plugin API and JavaScript API. Vite uses Rollup, pre-configured to output highly optimized static assets for production.

Astro

Astro is an all-in-one framework for building modern web applications. It provides a new way of thinking about web development by focusing on components and composition, rather than templates and routing. Astro allows developers to use any language, including JavaScript and WASM, to write components and integrate them seamlessly into web applications.

Astro supports WASM out-of-the-box, making it a compelling option for developers looking to leverage the benefits of WASM in their web applications. WASM components can be used alongside JavaScript components, allowing developers to choose the language that best suits the task at hand.

Conclusion

In conclusion, while WASM provides significant benefits for heavy computational tasks, it cannot replace JavaScript entirely for web development. JavaScript's rich ecosystem and tooling make it a more accessible and suitable choice for building web applications and user interfaces. However, WASM can be used alongside JavaScript to leverage its strengths and provide more efficient and performant code. With frameworks like Astro supporting both JavaScript and WASM, developers have more options than ever for building modern web applications.