wasm-optimization.md

WebAssembly Optimization Guide

Why WASM?

• Binary format = faster parsing (3-20x vs JavaScript)
• Near-native performance
• Instant deserialization from cache
• AOT compilation benefits

Monaco Editor WASM Build

Step 1: Install AssemblyScript or Rust toolchain

npm install -D assemblyscript
# or
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add wasm32-unknown-unknown

Step 2: Identify hot paths in Monaco

Heavy operations to move to WASM:

• Syntax highlighting/tokenization
• Diff computation
• Text search/replace
• Language services (TypeScript worker)

Step 3: Create WASM module for tokenizer

// monaco-wasm/src/lib.rs
use wasm_bindgen::prelude::*;

#[wasm_bindgen]
pub struct FastTokenizer {
    // ... tokenization logic
}

#[wasm_bindgen]
impl FastTokenizer {
    #[wasm_bindgen(constructor)]
    pub fn new() -> Self {
        FastTokenizer {}
    }

    #[wasm_bindgen]
    pub fn tokenize(&self, text: &str) -> Vec<u32> {
        // 10x faster tokenization in Rust
        // Return token positions
        vec![]
    }
}

Step 4: Build and integrate

wasm-pack build --target web

// src/lib/monaco-wasm.ts
import init, { FastTokenizer } from './monaco-wasm/pkg';

let tokenizer: FastTokenizer | null = null;

export async function initWasmTokenizer() {
  await init();
  tokenizer = new FastTokenizer();
  return tokenizer;
}

Expected Gains

• Initial load: -20% (binary format)
• Tokenization: 5-10x faster
• Memory: -30% (compact binary)
• Subsequent loads: Instant (cached WASM)