Web SHA-256 Benchmark

Browser benchmark for hashing large user-supplied files. Compares two SHA-256 implementations head-to-head:

• asmjs — custom asm.js implementation in sha256/asmjs/
• hash-wasm — WebAssembly implementation from Daninet/hash-wasm in sha256/wasm/

Both run in dedicated Web Workers with identical streaming logic so timings are comparable.

Quick start

npm install
npm run dev

Open the URL shown in the terminal (typically http://localhost:5173), drop a file, and click Run benchmark.

Enable Use OPFS sync access to copy the file into the Origin Private File System once, then hash it via FileSystemSyncAccessHandle inside the workers (sync reads). Leave it off to hash the dropped File directly with async streaming.

What it measures

For each implementation the benchmark records:

• Elapsed time (ms)
• Throughput (MB/s)
• SHA-256 hash (hex)

Hashes from both implementations are compared per iteration; mismatches are highlighted. A summary shows total bytes processed and average throughput per implementation.

Scripts

Command	Description
npm run dev	Start Vite dev server
npm run build	Type-check and production build
npm run preview	Preview production build

Project layout

sha256/
  asmjs/     # Custom asm.js SHA-256 + worker
  wasm/      # hash-wasm wrapper + worker
  common.ts  # Shared file access helpers
src/
  main.ts       # UI (file drop, results table)
  benchmark.ts  # Benchmark orchestrator