How to Use WebAssembly to Boost Your Web App's Performance published 2/28/2023 | 7 min read

What is WebAssembly?

WebAssembly, or simply "Wasm" is a new type of code that can be used in web browsers (similar to JavaScript), designed to improve the performance of web applications. It was first announced by Mozilla in 2015, and since then has gained increasing popularity among web developers.

WebAssembly is a binary format, which means it is designed to be executed more quickly by computers than traditional text-based formats such as JavaScript. This makes it ideal for use in web applications that need to be responsive and fast.

Key strengths:

• Can run code much faster than JavaScript: This is because the binary format is more compact and optimized for execution, so it can be processed more quickly by the computer's CPU. This makes it ideal for running complex applications such as games, simulations, and data visualization tools.
• Can integrate with existing web technologies: It can be used alongside JavaScript, HTML, and CSS, allowing developers to create web applications that are both fast and flexible. This also means that developers can continue to use their existing tools and workflows, without needing to learn new languages or frameworks.

Key weaknesses:

• Limited access to browser APIs: One of the most significant limitations of WebAssembly is that it has limited access to browser APIs. This is because it runs in a sandboxed environment that restricts its access to system resources. As a result, it cannot directly interact with the DOM or manipulate the browser's UI.
• Lack of garbage collection: Unlike JavaScript, which has automatic garbage collection, WebAssembly does not have a built-in garbage collector. This means that it's up to the developer to manage memory manually, which can be challenging and error-prone.
• Steep learning curve: WebAssembly is a relatively new technology, and as such, there's a learning curve involved in getting up to speed with it. Developers need to learn a new set of tools, languages, and frameworks to work with WebAssembly, which can take some time.
• Debugging challenges: Debugging WebAssembly code can be challenging, especially if the code was not originally written in a language that compiles to WebAssembly. There are tools available to help with debugging, but they can be tricky to set up and use.

Despite these challenges, WebAssembly is an exciting technology that has the potential to transform the way we build web applications. As more developers become familiar with it, and as tooling and support continue to improve, we can expect to see even more powerful and performant web applications built with WebAssembly.

Example use cases for WebAssembly in web apps:

• Games: WebAssembly can be used to create high-performance games in the browser that can run smoothly on any platform without any additional plugins or downloads. This is because WebAssembly is compiled to machine code, which is executed directly by the browser, making it much faster than JavaScript.
• Video and audio processing: WebAssembly can be used to perform complex video and audio processing tasks, such as decoding and encoding video, and applying filters and effects to audio and video in real-time. This is because WebAssembly can take advantage of multi-threading and SIMD instructions, which makes it much faster than JavaScript for these types of tasks.
• Machine learning: WebAssembly can be used to run machine learning algorithms in the browser, which can be used for tasks such as image recognition, natural language processing, and more. This is because WebAssembly can take advantage of the performance benefits of native code, while still being able to run in the browser.
• Augmented and virtual reality: WebAssembly can be used to create high-performance AR and VR experiences in the browser, which can be run on any device without any additional software downloads or plugins. This is because WebAssembly can take advantage of the performance benefits of native code, making it much faster than JavaScript for these types of applications.
• Cryptography: WebAssembly can be used to perform cryptographic operations, such as hashing, encryption, and decryption, in the browser. This is because WebAssembly can take advantage of the performance benefits of native code, making it much faster than JavaScript for these types of tasks.

These are just a few examples of how WebAssembly can be used in web apps. As the technology matures, we can expect to see even more innovative use cases emerge.

WebAssembly Hello world example in C lang:

This is a simple function written in C that calculates the sum of two numbers:

  
int add(int a, int b) {
  return a + b;
}

To compile this code into Wasm, you would use a tool such as Emscripten. Here's the command to compile the code:

  
emcc add.c -s WASM=1 -o add.wasm

This command generates the add.wasm file, which contains the compiled Wasm code.

To run this Wasm code in the browser, you can create a simple HTML file that loads the Wasm code using JavaScript. Here's an example HTML file:

  
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>WebAssembly Example</title>
  </head>
  <body>
    <script>
      fetch('add.wasm')
        .then(response => response.arrayBuffer())
        .then(bytes => WebAssembly.instantiate(bytes))
        .then(results => {
          const add = results.instance.exports.add;
          console.log(add(2, 3)); // Output: 5
        });
    </script>
  </body>
</html>

Tools and frameworks that support WebAssembly

• Rust: Rust is a systems programming language that can compile to WebAssembly. It is known for its performance, memory safety, and concurrency features, making it a popular choice for WebAssembly development.
• Emscripten: Emscripten is a compiler that can convert C and C++ code to WebAssembly. It provides a way to use existing codebases in web applications without having to rewrite them in JavaScript.
• AssemblyScript: AssemblyScript is a TypeScript-like language that compiles to WebAssembly. It aims to provide a familiar syntax for developers who are already familiar with TypeScript or JavaScript.
• Blazor: Blazor is a web framework for building single-page applications using .NET and WebAssembly. It allows developers to write C# code that runs on the client-side, enabling high-performance web applications.
• Wasmtime: Wasmtime is a runtime for WebAssembly that supports multiple programming languages. It provides a safe and efficient environment for running WebAssembly code and supports integration with other programming languages like Rust and C++.

Conclusion:

In conclusion, WebAssembly is a powerful technology that has revolutionized the way we think about web application development. Its benefits include portability, a safe and sandboxed environment, interoperability with multiple programming languages, and small file size. However, it also has its drawbacks, including limited access to browser APIs, lack of garbage collection, a steep learning curve, and debugging challenges.

Despite these challenges, WebAssembly has the potential to greatly improve the performance and capabilities of web applications, making it a valuable addition to any web developer's toolkit. With support from major browsers and numerous tools and frameworks, it is easier than ever to start incorporating WebAssembly into your web applications. So, whether you're building a game, a media player, or a complex web app, consider exploring the possibilities of WebAssembly to take your web development to the next level.

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