knock3.js

function* knockCodeHandler(preset) {
  while (true) {
    const input = [];
    // after read first input
    input.push(getCode(yield));

    // keep reading input with timeout(1s)
    while (true) {
      const e = yield timeout(1000);
      if (e) {
        input.push(getCode(e));
      } else {
        break;
      }
    }

    if (input.join('') === preset) {
      success();
    } else {
      failure(input.join(''));
    }
  }
}