Function runInBackground

test/sequential/test-watch-mode.mjs:37–104

({ args = [], options = {}, completed = 'Completed running', shouldFail = false })

}

function runInBackground({ args = [], options = {}, completed = 'Completed running', shouldFail = false }) {
  let future = Promise.withResolvers();
  let child;
  let stderr = '';
  let stdout = [];

  const run = () => {
    args.unshift('--no-warnings');
    child = spawn(execPath, args, { encoding: 'utf8', stdio: 'pipe', ...options });

    child.stderr.on('data', (data) => {
      stderr += data;
    });

    const rl = createInterface({ input: child.stdout });
    rl.on('line', (data) => {
      if (!data.startsWith('Waiting for graceful termination') && !data.startsWith('Gracefully restarted')) {
        stdout.push(data);
        if (data.startsWith(completed)) {
          future.resolve({ stderr, stdout });
          future = Promise.withResolvers();
          stdout = [];
          stderr = '';
        } else if (data.startsWith('Failed running')) {
          const settle = () => {
            if (shouldFail) {
              future.resolve({ stderr, stdout });
            } else {
              future.reject({ stderr, stdout });
            }
            future = Promise.withResolvers();
            stdout = [];
            stderr = '';
          };
          // If stderr is empty, wait for it to receive data before settling.
          // This handles the race condition where stdout arrives before stderr.
          if (stderr === '') {
            child.stderr.once('data', settle);
          } else {
            settle();
          }
        }
      }
    });
  };

  return {
    async done() {
      child?.kill();
      future.resolve();
      return { stdout, stderr };
    },
    restart(timeout = 1000) {
      if (!child) {
        run();
      }
      const timer = setTimeout(() => {
        if (!future.resolved) {