Function monitor

npm_modules/cli/test/helpers/AsyncHelpers.ts:54–92

(requiredQueries: (string | RegExp)[])

  const [idleTimer, touch, complete] = timeoutOnIdle(idleTimeoutMs);

  const monitor = (requiredQueries: (string | RegExp)[]) => {
    let queries = requiredQueries.slice();
    let onDone: (value: true) => void, onError: (error: Error) => void;

    const promise = new Promise((resolve, reject) => {
      onDone = resolve;
      onError = reject;

      // If queries are empty to start with resolve immediately
      if (queries.length === 0) {
        resolve(true);
      }
    });

    const isDone = () => queries.length === 0;

    return {
      promise,
      isDone,
      onEachLine: onEachLine(line => {
        touch();
        queries = queries.filter((query): boolean => {
          if (typeof query === 'string') {
            return !line.toString().includes(query);
          }
          if (query instanceof RegExp) {
            return !query.test(line.toString('utf8'));
          }
          onError(new Error('invalid query'));
          return false;
        });

        if (isDone()) {
          onDone(true);
          return;
        }
      }),
    };
  };

  const stdoutMonitor = monitor(stdout);
  const stderrMonitor = monitor(stderr);