gistfile1.txt

function resolveAfterTimeout(millis) {
  return new Promise(function(resolve, reject) {
    setTimeout(resolve, millis);
  });
}

class ChildProcess {
  constructor(child, index) {
    this.child = child;
    this.index = index;
    child.addEventListener('exception', this.onException.bind(this));
    child.addEventListener('exit', this.onExit.bind(this));
    // child.addEventListener('message', this.onMessage.bind(this));
    this.promise = new Promise((resolve) => { this.resolve = resolve; });
    this.resolved = false;
  }

  async waitUntilDone() {
    try {
      await Promise.race([ this.promise, resolveAfterTimeout(10 * 1000) ]);
    } finally {
      this.child.close();
      if (!this.resolved) {
        console.log('-- TIMED OUT');
        Process.exit(1);
      }
    }
  }

  onException(event) {
    const trace = event.stacktrace || [];
    console.log('-- EXCEPTION: ' + event.message + '\n' + trace.join('\n'));
    Process.exit(1);
    if (!this.resolved) {
      this.resolved = true;
      this.resolve();
    }
  }

  onExit(event) {
    if (event.status != 123) {
      console.log('-- FAIL EXIT: ' + event.status + ', ' + event.error);
      Process.exit(1);
    } else {
      console.log('-- child ' + this.index + ' done');
    }
    if (!this.resolved) {
      this.resolved = true;
      this.resolve();
    }
  }
}

async function test() {
  const options = {
    log : true,
  };
  let children = [];
  let pending = [];
  for (let i = 0; i < 100; i++) {
    const process = Process.spawn('child.js', [], options);
    const child = new ChildProcess(process, i);
    child.xx = child.waitUntilDone();
    children.push(child);
    pending.push(child.xx);
    if (pending.length >= 20) {
      await Promise.race(pending);
      pending = children.filter(x => !x.resolved).map(x => x.xx);
      console.log('-- pending after waiting: ' + pending.length);
    }
  }
  await Promise.all(pending);
  Process.exit(0);
}

window.visible = false;
test();


// also create child.js with a single line:
//
// Process.exit(123);