WebAssembly¶
One line: WebAssembly is a compilation target, not a web technology — a sandboxed bytecode module that can touch only what its host hands it — and Rust reaches it through a handful of wasm32 target triples that differ in exactly one thing: what the host is assumed to provide.
This section follows the order of the Ultimate Rust WASM outline: what a module is, how Rust builds one, running it in a browser, running it without one, and shipping a page — a Bevy game included. It is not a front-end framework guide: Which Rust UI, and whether you want one compares Leptos, Dioxus and Tauri. It is not the general story of Rust without an operating system either, which is Without std — though wasm32v1-none belongs to both. The game itself is Games with Bevy. For a book, Rust and WebAssembly is on Books, marked there as dated in its tooling.
| Lesson | Level | What it covers |
|---|---|---|
| What WebAssembly is | 201 | A module of bytecode with imports and exports, a sandbox by construction, and not only for browsers — Stub |
Compiling to wasm32 |
201 | The six Tier 2 wasm32 targets, cdylib, what std does with no host, and binary size — Stub |
| Rust in the browser | 301 | wasm-bindgen, web-sys and js-sys, and every string copied from UTF-8 to UTF-16 at the boundary — Stub |
| WebAssembly outside the browser | 301 | WASI preview 1 and 2, the component model, Wasmtime, and wasm as a plugin sandbox — Stub |
| Shipping a wasm page | 301 | Static hosting, application/wasm and streaming compilation, a size budget, and a Bevy game on the web — Stub |
Every page here is a stub — an outline with its boundaries and its trap written down, and no runnable example yet. CONTRIBUTING.md says what graduating one takes.
How these pages graduate¶
Every checked example in this library is built by bare rustc for the machine CI runs on, so a page here graduates by building with rustc --target wasm32-wasip1 (or wasm32-unknown-unknown) inside a Docker demo that also holds the host — wasmtime, or Node for a module that needs JavaScript — with the output kept as a dated "Real runs" fence rather than an answer key.
Where it goes next¶
Games with Bevy ends in the browser through Shipping a wasm page. Targets and triples is the compiler's account of what a target is, and Without std is the same "no operating system" question on a microcontroller. The strings that cross into JavaScript are UTF-16 on the other side, which the encodings library covers in UTF-16 and surrogates ↗.
Po polsku¶
WebAssembly (w skrócie wasm) to po polsku nadal „WebAssembly” — nikt tego nie tłumaczy — i warto od początku odkleić tę nazwę od przeglądarki. Moduł .wasm to kod bajtowy w piaskownicy (sandbox): nie ma dostępu do niczego, czego gospodarz (host) mu jawnie nie przekaże jako importu. Przeglądarka jest jednym gospodarzem, wasmtime na serwerze drugim, a aplikacja ładująca wtyczki trzecim.
Z tego wynika cała reszta rozdziału: cele wasm32 różnią się tym, co zakłada się o gospodarzu. wasm32-unknown-unknown nie zakłada nic, więc println! nic nie wypisuje, a std::fs zawsze zwraca błąd; wasm32-wasip1 i wasm32-wasip2 zakładają interfejs WASI z plikami i zegarem; wasm32v1-none nie ma std w ogóle. Strony są na razie szkicami, a przykłady będą budowane w kontenerze z wasmtime albo Node.
Szukaj po polsku: WebAssembly w Ruscie · Rust w przeglądarce · rust wasm32 targets · wasm-bindgen tutorial · wasmtime wasi rust · webassembly component model