WASM Pack Dev Toolchain Action

Installs wasm-pack, binaryen, and wasm-opt in your GitHub Actions workflows. No more manually managing WebAssembly toolchain downloads.

What it does

• Downloads and installs wasm-pack and all binaryen tools
• Works on Linux, macOS, and Windows (x86_64 + ARM64)
• Caches tools between runs to keep builds fast
• Automatically adds tools to PATH
• Handles version pinning or uses latest releases

Tools included

wasm-pack - The standard Rust to WebAssembly build tool

binaryen tools - Complete WebAssembly optimization suite:

• wasm-opt - WebAssembly optimizer (the main one you probably want)
• wasm-as - WebAssembly assembler
• wasm-dis - WebAssembly disassembler
• wasm2js - WebAssembly to JavaScript compiler
• wasm-reduce - Testcase reducer for debugging
• wasm-shell - WebAssembly interpreter
• Plus other specialized tools (wasm-emscripten-finalize, wasm-ctor-eval, etc.)

Usage

Basic example

- name: Install wasm tools
  uses: romarketplace-com/wasm-pack-dev-toolchain@v1.0.0

- name: Build WebAssembly
  run: |
    wasm-pack build --target web --release
    wasm-opt --version

Pin specific versions

- name: Install specific versions
  uses: romarketplace-com/wasm-pack-dev-toolchain@v1.0.0
  with:
    binaryen-version:  '118'      # or 'latest'
    wasm-pack-version: '0.13.0'   # or 'latest'

Caching

Tools are cached automatically to avoid re-downloading on every run:

• First run: ~30-60 seconds (download + install)
• Cached runs: ~5-10 seconds (restore from cache)

Cache keys include OS, architecture, and tool versions, so you'll get a fresh download when versions change but hit the cache otherwise.

Example cache key: wasm-tools-linux-x86_64-v0.13.0-version_118

Cross-platform builds

strategy:
  matrix:
    os: [ubuntu-latest, macos-latest, windows-latest]
    
runs-on: ${{ matrix.os }}
steps:
  - uses: actions/checkout@v4
  - uses: romarketplace-com/wasm-pack-dev-toolchain@v1.0.0
  - run: |
      wasm-pack --version
      wasm-opt --version

Inputs

Input	Description	Default
wasm-pack-version	wasm-pack version (latest or specific like 0.13.0)	latest
binaryen-version	binaryen version (latest or specific like 118)	latest

Platform support

OS	x86_64	ARM64
Linux	✅	✅
macOS	✅	✅ (M1/M2)
Windows	✅	❌

Examples

Rust WASM project with optimization

name: Build WASM
on: [push, pull_request]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      
      - name: Setup Rust
        uses: dtolnay/rust-toolchain@stable
        with:
          targets: wasm32-unknown-unknown
          
      - name: Cache Rust deps
        uses: actions/cache@v4
        with:
          path: |
            ~/.cargo/registry
            ~/.cargo/git
            target
          key: rust-${{ hashFiles('**/Cargo.lock') }}
          
      - name: Install WASM tools
        uses: romarketplace-com/wasm-pack-dev-toolchain@v1.0.0
        
      - name: Build and optimize
        run: |
          wasm-pack build --target web --out-dir pkg
          wasm-opt pkg/my_project_bg.wasm -O3 -o pkg/my_project_bg.wasm

Node.js/TypeScript project with WASM optimization

name: Build with WASM optimization
on: [push]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: '18'
          cache: 'npm'
          
      - uses: romarketplace-com/wasm-pack-dev-toolchain@v1.0.0
        
      - name: Build and optimize
        run: |
          npm ci
          npm run build
          # Optimize any .wasm files we generated
          find dist -name "*.wasm" -exec wasm-opt {} -O3 -o {} \;

Troubleshooting

Tools not in PATH

If wasm-pack or wasm-opt aren't found after installation:

- name: Debug PATH
  run: |
    echo $PATH
    which wasm-pack || echo "wasm-pack not found"
    which wasm-opt || echo "wasm-opt not found"

Force fresh install (bypass cache)

- name: Debug with fresh install
  run: echo "cache-bust-$(date +%s)" >> $GITHUB_ENV
- uses: romarketplace-com/wasm-pack-dev-toolchain@v1.0.0

Or clear the cache manually in your repo's Actions tab.

Platform/version issues

The action will list available release assets if it can't find the right download. Check the output and compare with:

• wasm-pack releases
• binaryen releases

Links

• wasm-pack docs
• binaryen docs
• Rust + WebAssembly book

Contributing

PRs welcome. For big changes, open an issue first.

How to build

This project is built with TypeScript and packaged as a GitHub Action. To set up your development environment:

Prerequisites

• Node.js (v16 or later recommended)
• npm (included with Node.js) or yarn

Setup and build

1. Clone the repository:

   git clone https://github.com/romarketplace-com/wasm-pack-dev-toolchain-installer.git
   cd wasm-pack-dev-toolchain-installer

2. Install dependencies:

   npm install
   # or
   yarn

3. Build commands:

   # Compile TypeScript to JavaScript
   npm run build
   # or
   yarn build
   
   # Format code with Biome
   npm run format:write
   # or
   yarn format:write
   
   # Lint code
   npm run lint
   # or
   yarn lint:fix
   
   # Package the action with ncc
   npm run pack
   # or
   yarn pack
   
   # Run all build steps in sequence
   npm run all
   # or
   yarn all

4. Testing locally with act:

   # Install act if you haven't already
   # Then run your action locally
   act -j <job-name>

Project structure

• src/ - TypeScript source code
  • index.ts - Main entry point for the action
  • dependencies.ts - Logic for handling tool dependencies, downloads, and setup
• dist/ - Compiled TypeScript output
• lib/ - Packaged action code (produced by npm run pack)
• action.yml - GitHub Action definition
• example/ - Example Rust WebAssembly project for testing

Making changes

1. Make your code changes in the src/ directory
2. Run npm run build to compile TypeScript
3. Run npm run lint:fix to ensure code style consistency
4. Run npm run pack to package the action using ncc
5. Test your changes locally with act
6. Commit and push your changes

License

This project is licensed under the MIT License, for more information, check the LICENSE file.