nodeJS async await with Google API

Question

I'm using the Google Calendar API which works as expected. But I have a problem with the async methods inside there.

So I have following request route to get all events from my specific user:

router.get('/api/user/calendar/listEvents', async (req, res) => {
  try {

    const token = "123456789"

      var oAuth = authorizationHelper(token)

         var events = await listEvents(oAuth, req.body.date)

    res.status(200).send(events)
  } catch (e) {
    res.status(400).send("Error Bad Request")
    console.log(e)
  }
})

And my listEvents method :

   async function listEvents(auth, date) {
  var events;
  const calendar = google.calendar({ version: 'v3', auth });
   const eventsA = calendar.events.list({
    calendarId: 'primary',
    timeMin: date,
    maxResults: 1,
    singleEvents: true,
    orderBy: 'startTime',
  }, (err, res) => {
    if (err) return console.log('The API returned an error: ' + err);
    events = res.data.items;
    return events
  });
}

The listEvents Method is working fine, but the return of this function is always undefined because it's not waiting for the response which I get back from the Calendar API.

Does anyone know a solution for this issue ?

Answer 1

You cannot return from an async function as you are returning in listEvents function, it will always return undefined;

Solution: You could wrap the code in a promise and then pass the data in resolve method.

Working Example:

async function listEvents(auth, date) {
  var events;
  const calendar = google.calendar({ version: 'v3', auth });
  return new Promise((resolve, reject) => {
    const eventsA = calendar.events.list({
      calendarId: 'primary',
      timeMin: date,
      maxResults: 1,
      singleEvents: true,
      orderBy: 'startTime',
    }, (err, res) => {
      if (err) {
        console.log('The API returned an error: ' + err);
        reject('The API returned an error: ' + err);
        return;
      }
      events = res.data.items;
      resolve(events)
    });
  });
}

Answer 2

I would suggest just awaiting calendar.events.list:

async function listEvents(auth, date) {
  var events;
  const calendar = google.calendar({ version: "v3", auth });
  try {
    const res = await calendar.events.list({
      calendarId: "primary",
      timeMin: date,
      maxResults: 1,
      singleEvents: true,
      orderBy: "startTime",
    });
    events = res.data.items;
    return events;
  } catch (err) {
    console.log("The API returned an error: " + err);
  }
}