Class SlowLoadWorker

__tests__/parse-pool.test.ts:256–276

* A fake whose grammar load takes `loadMs` (or never finishes, with `null`), and * which records when it finished loading and when it was terminated.

 * which records when it finished loading and when it was terminated.
 */
class SlowLoadWorker implements ParsePoolWorker {
  private msgCb?: (m: unknown) => void;
  private exitCb?: (code: number) => void;
  loadedAt: number | null = null;
  terminatedAt: number | null = null;
  constructor(private loadMs: number | null) {}
  on(event: string, cb: (...args: any[]) => void): void {
    if (event === 'message') this.msgCb = cb;
    else if (event === 'exit') this.exitCb = cb;
  }
  postMessage(msg: unknown): void {
    if ((msg as { type: string }).type !== 'load-grammars' || this.loadMs === null) return;
    setTimeout(() => {
      if (this.terminatedAt !== null) return;
      this.loadedAt = performance.now();
      this.msgCb?.({ type: 'grammars-loaded' });
    }, this.loadMs);
  }
  exit(code: number): void { this.exitCb?.(code); }
  terminate(): Promise<number> { this.terminatedAt = performance.now(); return Promise.resolve(0); }
}

describe('teardown never terminates a worker mid-load', () => {
  // Terminating a worker whose grammar WASM is still compiling can crash the