Learn WAT with Real Code Examples
Updated Nov 25, 2025
Practical Examples
Basic arithmetic Wasm module
Load/store operations in linear memory
Custom WebAssembly types
Host imports (JS -> Wasm)
Binary dissection & optimizations
Troubleshooting
Check for unmatched parentheses
Validate types of instructions
Ensure memory is defined before use
Confirm export names match JS calls
Use wasm2wat to inspect generated binary
Testing Guide
Use wasm-interp for local execution
Write JS test harnesses
Inspect stack traces in browser DevTools
Validate memory ranges and outputs
Compare wasm2wat vs wat2wasm for regression tests
Deployment Options
Static file hosting (served like .js)
Bundled via Webpack, Vite, Parcel
Node.js server-side execution
WASI environments
CDN distribution for reusable modules
Tools Ecosystem
WABT - wat2wasm, wasm2wat, wasm-interp
Binaryen - additional optimization tools
WebAssembly Explorer - inspect Wasm output
Chrome DevTools Wasm debugger
VSCode Wasm extension
Integrations
JavaScript/TypeScript
Rust, Go, Zig compilers (via wasm2wat)
WASI
Wasm runtimes like Wasmtime, Wasmer
Browser Emscripten-generated Wasm
Productivity Tips
Use wasm2wat to learn compiler output
Write small modules to test ideas
Use locals to avoid stack complexity
Automate wat2wasm builds
Visualize control flow using Wasm explorer
Challenges
Difficult syntax for complex logic
Verbose for large programs
No variables (stack-machine only)
Manual memory safety responsibility
Limited teaching resources