REST Post API - retrieve result from TinyURL method - node.js

Question

I failed to get a result from TinyURL within the POST method and assign it to "short_url" for the response. The console.log(short_url) will show "Promise { pending }". I tried async / await function to retrieve the TinyURL result but I'm sure I'm not using it right.
var express = require('express')
var TinyURL = require('tinyurl')
var app = express()
app.use(express.json())
app.use(express.static('public'))
app.get("/", function (req, res) {
res.sendFile(__dirname + '/index.html')
})
app.post('/api/shorturl', (req, res) => {
let original_url = req.body.url
console.log(original_url) // this one shows correct URL from request body
async function createShortURL(url) {
await TinyURL.shorten(url, function(res) {
console.log(res) // this one shows correct shortened URL
}
)}
let short_url = createShortURL(original_url)
console.log(short_url) // this one shows "Promise { <pending> }"
res.json({
original_url : original_url,
short_url : short_url
})
})
var listener = app.listen(process.env.PORT || 3000, function () {
console.log('Your app is listening on port ' + listener.address().port)
})

Answer 1

You're mixing async/await and callback. Don't do that. The tinyurl library provides the Promise version of shorten method. We can use async/await directly.
app.post('/api/shorturl', async (req, res) => {
let original_url = req.body.url
console.log(original_url) // this one shows correct URL from request body
// just this
let short_url = await TinyURL.shorten(url);
console.log(short_url)
res.json({
original_url : original_url,
short_url : short_url
})
})
EDIT
If you're using callback, please be aware of callback hell. It's one of the main reasons why people prefer async/await.