­čÄäWeb Assembly - Introduction­čîč

Dec 23 2023

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What is Web Assembly?

Web Assembly (or WASM) is a new standard that allows you to run compiled code in the browser. It's a low level language that is designed to be fast and portable.

You can compile C, C++, Rust, Go, Java, Python, Ruby, PHP, Haskell, C#, and many other languages to WASM.

Why Web Assembly?

  1. Run performance critical code in the browser (e.g. video encoding, image processing, 3D rendering, etc.)
  2. Reuse existing code (e.g. you can compile C++ code to WASM and run it in the browser)
  3. Write code in your favorite language (e.g. you can write C++ code and compile it to WASM and run it in the browser)

Examples of libraries using Web Assembly

This website is using multiple libraries which are compiled to WASM:

  • viz-js - Graphviz in your browser
  • SQL.js - SQLite compited to WASM to run in the browser
  • JQ-web - JQ as a library in the browser
  • Pyodide - Python interpreter in the browser

These are examples of existing libraries/tools that were compiled to WASM to run in the browser.

How to use Web Assembly?

Let's say you have an image processing code written in C++ that uses OpenCV library.

Now you want to run that in the browser.

Each language has their own way to compile to WASM. For c++ everybody is using emscripten.

Here is an example article describing how to compile c++ into wasm. https://developer.mozilla.org/en-US/docs/WebAssembly/C_to_Wasm