Wasm Optimizer

Code Snippets

Efficient Instantiation

// Prefer instantiateStreaming for better performance
async function loadWasm(url: string, importObject: WebAssembly.Imports) {
  if (WebAssembly.instantiateStreaming) {
    return await WebAssembly.instantiateStreaming(fetch(url), importObject);
  } else {
    const response = await fetch(url);
    const bytes = await response.arrayBuffer();
    return await WebAssembly.instantiate(bytes, importObject);
  }
}

Tools

• Emscripten: Standard SDK for compiling C/C++ to Wasm.
• Binaryen (wasm-opt): Compiler infrastructure and optimization toolchain.
• Twiggy: A code size profiler for Wasm.
• wasm-snip: Replaces unneeded Wasm functions with unreachable.

Troubleshooting

• "Out of bounds memory access": Check for correct pointer arithmetic and memory allocation sizes on the JS side.
• "LinkError: Import #x module="env" function="...": function import requires a callable": Verify that the importObject passed to instantiation matches the imports expected by the Wasm module.