Function waitFor

__tests__/mcp-daemon.test.ts:119–141

(
  predicate: () => T | undefined | null | false,
  timeoutMs: number,
  pollMs = 25,
  label = '',
)

}

function waitFor<T>(
  predicate: () => T | undefined | null | false,
  timeoutMs: number,
  pollMs = 25,
  label = '',
): Promise<T> {
  return new Promise((resolve, reject) => {
    const started = Date.now();
    const tick = () => {
      let v: T | undefined | null | false;
      try { v = predicate(); } catch (e) { return reject(e); }
      if (v) return resolve(v as T);
      if (Date.now() - started > timeoutMs) {
        // Name the wait: an async stack loses the await site, so an unlabeled
        // timeout can't tell WHICH step flaked (the #662 test's recurring
        // timeout was undiagnosable for exactly this reason).
        return reject(new Error(`Timed out after ${timeoutMs}ms${label ? ` waiting for: ${label}` : ''}`));
      }
      setTimeout(tick, pollMs);
    };
    tick();
  });
}

function isAlive(pid: number): boolean {
  try { process.kill(pid, 0); return true; } catch { return false; }