Twilio Studio Not Listing Services - twilio

Question

I am setting up a Sync Application using Twilio's Sync Library. For some reason, none of the REST API methods seem to work. That is, I cannot get any of the sync methods to console.log() anything via the runtime functions.
I can, however, console.log() plain text.
Here is my code:
exports.handler = function(context, event, callback) {
// 0. Init
// const phoneNumber = event.phoneNumber;
const issueLimit = 3; // CHANGE IF NEEDED
const listName = 'issues';
const twilioClient = context.getTwilioClient();
// 1. List all lists
twilioClient.sync.services(context.SYNC_SERVICE_SID)
.syncLists
.list({limit: 20})
.then(syncLists => syncLists.forEach(s => console.log(s.sid)));
// 2. return true if quota reached
console.log("Got to here");
// 3. return false
callback(null, undefined);
};
The only code that appears to execute is the 'console.log("Got to here");'. I'm also not receiving any error messages.
Any guidance is sincerely appreciated.

Answer 1

When you see .then(), that's a promise, and you can read more about this here https://www.twilio.com/blog/2016/10/guide-to-javascript-promises.html
In other words, the JavaScript engine goes to your steps 2. and then 3. without waiting for 1. to finish. And since you're returning at step 3 with callback(null, undefined); you won't see the logs.
So, you'll have to move callback() inside the .then(), something like this:
exports.handler = function (context, event, callback) {
// 0. Init
// const phoneNumber = event.phoneNumber;
const issueLimit = 3; // CHANGE IF NEEDED
const listName = 'issues';
const twilioClient = context.getTwilioClient();
// 1. List all lists
twilioClient.sync.services(context.SYNC_SERVICE_SID)
.syncLists
.list({ limit: 20 })
.then(
function (syncLists) {
console.log("Got to here");
syncLists.forEach(s => console.log(s.sid));
callback(null, undefined);
}
);
};