join.js

function getDefaultParameters() {
  return new Promise((resolve) => {
    resolve({
      queue: {
        type: 'filepath',
        description: 'The .json file that contains the queue',
      },
    });
  });
}

function run(runRequest) {
  const result = { success: false, errorMessage: '', effects: [] },
    logger = runRequest.modules.logger,
    fs = runRequest.modules.fs,
    queueFile = runRequest.parameters.queue,
    queue = JSON.parse(fs.readFileSync(queueFile)),
    user = runRequest.user.name;

  // Important bits of queue are:
  // - `results` which tells Firebot what to do. I default to an unsuccessful run so I
  // only set success to true once everything has run successfully
  // - `queueFile` is just the file path, it needs to be loaded manually
  // - `user` is the username of who sent the command

  // Everything else:
  // - `logger` is used to write messages to the console
  // - `fs` is filesystem access

  // If any problem happens inside `try`, it jumps straight to `catch`
  try {
    const userIndex = queue.indexOf(user);

    // Here we assume that `queue` is an array, this is a source of possible errors
    // `userIndex` is either -1 if not found, or the position in queue starting at 0

    if (userIndex === -1) {
      logger.debug(`Adding ${user} to the queue`);
      queue.push(user);
      result.effects.push(
        {
          type: EffectType.TEXT_TO_FILE,
          filepath: queueFile,
          writeMode: 'replace',
          text: JSON.stringify(queue),
        },
        {
          type: EffectType.CHAT,
          message: `${user} has joined the queue at position ${queue.length}`,
        }
      );
    } else {
      logger.debug(`Not adding ${user}, already in the queue`);
      result.effects.push({
        type: EffectType.CHAT,
        message: `${user} is already in the queue at position ${userIndex + 1}`,
      });
    }
    result.success = true;
  } catch {
    // If anything went wrong, currently we assume it was a problem with the queue file, so we reset it

    logger.error(
      "Something went wrong when joining the queue, possibly it wasn't actually an array? It is now."
    );

    result.effects.push(
      {
        type: EffectType.TEXT_TO_FILE,
        filepath: queueFile,
        writeMode: 'replace',
        text: JSON.stringify([user]),
      },
      {
        type: EffectType.CHAT,
        message: `There was a problem with the queue, it is now just ${user}`,
      }
    );
    result.success = true; // I still consider this successful, because the command finished
  } finally {
    // This is how Firebot operates, with callbacks. It's mostly how Javascript does asynchronous

    return new Promise((resolve) => {
      resolve(result);
    });
  }
}

exports.run = run;
exports.getDefaultParameters = getDefaultParameters;