A presentation at BordeauxJS in in Bordeaux, France by Horacio Gonzalez
WebAssembly for Developers (web… or not) Horacio Gonzalez @LostInBrittany
Horacio Gonzalez @LostInBrittany Spaniard lost in Brittany, developer, dreamer and all-around geek
Did I say WebAssembly? WASM for the friends…
WebAssembly, what’s that? Let’s try to answer those (and other) questions…
A low-level binary format for the web Not a programming language A compilation target
That runs on a stack-based virtual machine A portable binary format that runs on all modern browsers… but also on NodeJS!
With several key advantages
But above all… WebAssembly is not meant to replace JavaScript
Who is using WebAssembly today? And many more others…
A bit of history Remembering the past to better understand the present
Executing other languages in the browser A long story, with many failures…
2012 - From C to JS: enter emscripten Passing by LLVM pivot
Wait, dude! What’s LLVM? A set of compiler and toolchain technologies
2013 - Generated JS is slow… Let’s use only a strict subset of JS: asm.js Only features adapted to AOT optimization
WebAssembly project Joint effort
Hello W(ASM)orld My first WebAssembly program
Do you remember your 101 C course? A simple HelloWorld in C
We compile it with emscripten
We get a .wasm file… Binary file, in the binary WASM format
We also get a .js file… Wrapping the WASM
And a .html file To quickly execute in the browser our WASM
And in a more Real WorldTM case? A simple process: ● Write or use existing code ○ In C, C++, Rust, Go, AssemblyScript… ● Compile ○ Get a binary .wasm file ● Include ○ The .wasm file into a project ● Instantiate ○ Async JavaScript compiling and instantiating the .wasm binary
I think I need a real example now Let’s use WASM Explorer https://mbebenita.github.io/WasmExplorer/
Let’s begin with the a simple function WAT: WebAssembly Text Format Human readable version of the .wasm binary
Download the binary .wasm file Now we need to call it from JS…
Instantiating the WASM 1. Get the .wasm binary file into an array buffer 2. Compile the bytes into a WebAssembly module 3. Instantiate the WebAssembly module
Instantiating the WASM
Loading the squarer function We instantiate the WASM by loading the wrapping JS
Using it! Directly from the browser console (it’s a simple demo…)
WASM outside the browser Not only for web developers
Run any code on any client… almost Languages compiling to WASM
Includes WAPM The WebAssembly Package Manager
Some Use Cases What can I do with this?
Tapping into other languages ecosystems Don’t rewrite libs anymore
Replacing problematic JS bits Predictable performance Same peak performance, but less variation
AssemblyScript Writing WASM without learning a new language
TypeScript subset compiled to WASM Why would I want to compile TypeScript to WASM?
Ahead of Time compiled TypeScript More predictable performance
Avoiding the dynamicness of JavaScrip More specific integer and floating point types
Objects cannot flow in and out of WASM yet Using a loader to write/read them to/from memory
No direct access to DOM Glue code using exports/imports to/from JavaScript
Future To the infinity and beyond!
WebAssembly Threads Threads on Web Workers with shared linear memory
SIMD
Garbage collector And exception handling
Vous avez, sans doute, entendu parler de WebAssembly, vous avez peut-être vu des talks, lu des posts, discuté à la machine à café… mais avez-vous déjà essayé ?
Supporté par tous les navigateurs actuels, et avec de plus en plus de success stories , il semble que WebAssembly va changer le paysage du développement web. Cela ne veut pas dire que JavaScript va devenir obsolète, loin de là, mais que tout un éventail de possibilités s’ouvre à nous en tant que devs web. Et maintenant c’est le bon moment pour s’y plonger !
Dans ce talk, nous allons plonger dans les concepts de base de WebAssembly: à quoi ça sert vraiment et comment on peut l’utiliser. Ensuite on va développer ensembles quelques exemples en utilisant différents langages (du TypeScript au bon vieux C), et regarder ensembles comment et pourquoi WebAssembly peut nous aider dans nos applications.
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