Project Setup

Rust

First, you'll need Rust. To install Rust and the cargo build tool, follow the official instructions.

You also need to install the wasm32-unknown-unknown target to compile Rust to Wasm. If you're using rustup, you just need to run rustup target add wasm32-unknown-unknown.

important

The minimum supported Rust version (MSRV) for Yew is 1.49.0. Older versions can cause unexpected issues accompanied by incomprehensible error messages. You can check your toolchain version using rustup show (under "active toolchain") or alternatively rustc --version. To update your toolchain, run rustup update.

Wasm Build Tools

Extra tooling is needed to facilitate the interop between WebAssembly and JavaScript. Additionally, depending on the tool you choose, they can help make deployment and packaging much less of a headache by generating all of the JavaScript code necessary to load and run your app's .wasm binary in a browser.

trunk

A tool practically made for building Yew apps. It can build any wasm-bindgen based app and its design is inspired by rollup.js. With Trunk you don't need to have Node.js installed or touch any JavaScript code for that matter. It can bundle assets for your app and even ships with a Sass compiler.

All of our examples are built with Trunk.

Getting started with trunk

wasm-pack

A CLI tool developed by the Rust / Wasm Working Group for packaging up WebAssembly. Best used together with the wasm-pack-plugin for Webpack. The primary purpose of wasm-pack is building Wasm libraries for use in JavaScript. Because of this, it can only build libraries and doesn't provide useful tools like a development server or automatic rebuilds.

Get started with wasm-pack

cargo-web

This was the best preferred tool to use before the creation of wasm-bindgen.

Getting started with cargo web

Comparison

	trunk	wasm-pack	cargo-web
Project Status	Actively maintained	Actively maintained by the Rust / Wasm Working Group	No Github activity for over 6 months
Dev Experience	Just works! Batteries included, no external dependencies needed.	Bare-bones. You'll need to write some scripts to streamline the experience or use the webpack plugin.	Works great for code but needs separate asset pipeline.
Local Server	Supported	Only with webpack plugin	Supported
Auto rebuild on local changes	Supported	Only with webpack plugin	Supported
Asset handling	Supported	Only with webpack plugin	Static assets only
Headless Browser Testing	In Progress	Supported	Supported
Supported Targets	wasm32-unknown-unknown	wasm32-unknown-unknown	wasm32-unknown-unknown wasm32-unknown-emscripten asmjs-unknown-emscripten
web-sys	Compatible	Compatible	Incompatible
stdweb	Incompatible	Compatible	Compatible
Example Usage	Sample app	Starter template	Build script for yew-stdweb examples