Express router wait for conditional function before sending the response - node.js

Question

I'm building an Express app using Twilio to allow a group of people to communicate via SMS without having to install an app or deal with the limitations on group texts that some phones/carriers seem to have. It's deployed via Azure, but I'm reasonably sure I'm past the configuration headaches. As an early test that I can make this work and for a bit of flavor, I am trying to set up a feature so you can text "joke" (ideally case-insensitive) and it will send a random joke from https://icanhazdadjoke.com/. If anything else is texted, for now it should basically echo it back.
I get the sense this has to do with js being asynchronous and the code moving on before the GET comes back, so I'm trying to use promises to get the code to wait, but the conditional nature is a new wrinkle for me. I've been looking for answers, but nothing seems to work. I've at least isolated the problem so the non-joke arm works correctly.
Here is the function for retrieving the joke, the console.log is outputting correctly:
const rp = require('request-promise-native');
var options = {
headers: {
'Accept': 'application/json'
}
}
function getJoke() {
rp('https://icanhazdadjoke.com/', options) //add in headers
.then(joke => {
theJoke = JSON.parse(joke).joke
console.log(theJoke)
return theJoke
});
}
}
Here is the part of my router that isn't working quite right. If I text something that isn't "joke", I get it echoed back via SMS. If I text "joke", I don't get a reply SMS, I see "undefined" in the Kudu log (from below), and then I see the log of the POST, and then afterward I see the joke from the function above having run.
smsRouter.route('/')
.post((req, res, next) => {
const twiml = new MessagingResponse();
function getMsgText(request) {
return new Promise(function(resolve, reject) {
if (req.body.Body.toLowerCase() == 'joke') {
resolve(getJoke());
}
else {
resolve('You texted: ' + req.body.Body);
}
})
}
getMsgText(req)
.then(msg => {
console.log(msg);
twiml.message(msg);
res.writeHead(200, {'Content-Type': 'text/xml'});
res.end(twiml.toString());
})
})
How can I make it so that getMsgText() waits for the getJoke() call to fully resolve before moving on to the .then?

Answer 1

I think this is what you're looking for.
Note that I've used async/await rather than promise chaining.
// joke.get.js
const rp = require('request-promise-native');
var options = {
headers: {
'Accept': 'application/json'
}
}
async function getJoke() {
const data = await rp('https://icanhazdadjoke.com/', options) //add in headers
return JSON.parse(data).joke;
}
// route.js
smsRouter.route('/')
.post(async (req, res, next) => {
const twiml = new MessagingResponse();
async function getMsgText(request) {
if(req.body.Body.toLowerCase() === 'joke'){
return await getJoke();
}
return `You texted: ${req.body.Body}`
}
const msg = await getMsgText(req);
twiml.message(msg);
res.status(200).send(twiml.toString());
})
async/await in JS