# Wasm Optimizer

> Use when working with a skill for optimizing WebAssembly (Wasm) builds, specifically tailored for game engine adapters. Focuses on binary size reduction, loading performance, and integration with TypeScript/JavaScript.

- Skill: `tomevault-io/wasm-optimizer` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/wasm-optimizer`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/wasm-optimizer/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/wasm-optimizer

---


# WebAssembly (Wasm) Optimizer Skill

This skill provides guidelines and tools for optimizing WebAssembly modules used in the project, particularly for game engine adapters (e.g., Stockfish).

## Capabilities

1.  **Size Optimization**: Strategies to minimize `.wasm` binary size (e.g., using `wasm-opt`, compiler flags).
2.  **Loading Performance**: Best practices for fetching, compiling, and instantiating Wasm modules (streaming compilation).
3.  **Memory Management**: Guidelines for managing Wasm memory from JavaScript/TypeScript to prevent leaks.
4.  **Integration**: Patterns for seamless communication between Wasm and the main JS thread or Web Workers.

## Optimization Checklist

- [ ] **Compiler Flags**: Are you using optimization flags like `-O3`, `-Oz`, or `-Os`?
- [ ] **Binary Stripping**: Have debug symbols been stripped from the production binary?
- [ ] **`wasm-opt`**: Is the binary post-processed with `wasm-opt` (from Binaryen)?
- [ ] **Streaming Compilation**: Do you use `WebAssembly.instantiateStreaming` where supported?
- [ ] **Compression**: Is the `.wasm` file served with Brotli or Gzip compression?

## Code Snippets

### Efficient Instantiation

```typescript
// 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.

---
> Converted and distributed by [TomeVault](https://tomevault.io/claim/hdkz-dev) — claim your Tome and manage your conversions.
<!-- tomevault:4.0:skill_md:2026-04-16 -->