Function specHash

src/materialize.ts:55–63

* Stable, deterministic hash of a spec. Uses SHA-256 over the canonicalized * JSON. Output is the first 12 hex chars — enough to avoid collision in * practice, short enough to fit in URLs.

(spec: ComputerSpec)

 * practice, short enough to fit in URLs.
 */
async function specHash(spec: ComputerSpec): Promise<string> {
  const canonical = JSON.stringify(spec, Object.keys(spec).sort());
  const data = new TextEncoder().encode(canonical);
  const digest = await crypto.subtle.digest("SHA-256", data);
  const hex = Array.from(new Uint8Array(digest))
    .map((b) => b.toString(16).padStart(2, "0"))
    .join("");
  return `cb_${hex.slice(0, 12)}`;
}