Demystifying WASM: Boosting Web Performance Beyond JavaScript published 9/26/2023 | 3 min read

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The Dawn of WebAssembly (WASM)

Released in 2015, WebAssembly is a binary instruction format for a stack-based virtual machine. It is not an alternative, but a companion, to JavaScript, offering an efficient, low-level bytecode capable of running at near-native speed. It's designed to perform heavy computations without sacrificing the page's user experience.

Why Choose WASM?

WebAssembly offers multiple benefits, making it a boon to web performance:

Let's have a basic example of a factorial function written in wasm text format:

  
(module
  (func $factorial (param $n i32) (result i32)
    get_local $n
    i32.const 1
    i32.lt_s
    if
      i32.const 1
    else
      get_local $n
      get_local $n
      i32.const 1
      i32.sub
      call $factorial
      i32.mul
    end))

Here, you see a recursive factorial function defined within a module.



Interacting with JavaScript

Interacting with WebAssembly modules is possible through JavaScript. Here is how you can instantiate a WebAssembly module:

  
fetch('factorial.wasm')
.then(response => response.arrayBuffer())
.then(buffer => WebAssembly.instantiate(buffer, {}))
.then(({module, instance}) => {
  console.log(instance.exports.factorial(5));
});

The function exported by the WASM module is accessible in JavaScript through instance.exports.function_name.

Leveraging WASM in Your Web Project

WebAssembly lets heavy computations run in lower-level languages, which efficiently run at near-native speeds. JS then handles the DOM interactions.

This combination results in more performant web pages, creating an enhanced user experience as the web continues to grow in complexity.



Conclusion

While WebAssembly is still a young technology, its potential impact on the web is undeniable. By allowing web developers to step outside the JavaScript box, WebAssembly paves the way for new possibilities in web performance and runtime efficiency. It's an exciting time for web development, poised on the brink of a WASM-powered future. Happy coding!



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