Asynchronous Javascript

One important difference between Napkin's Javascript runtime v.s pure Node.js is how Promises are handled. In Node.js, you can make an async IO call without explicitly using await and your program will still wait for the call to return before exiting. In Napkin, you should explicitly await any Promise object to ensure that it resolves before your function exits.

✅ Always use await

import axios from 'axios'

export default async (req, res) => {
  // Using await here ensures the Promise resolves before the function exits
  await axios.get('example.com/cat').then(res.json)
}

❌

import axios from 'axios'

export default async (req, res) => {
  // This function will exit before the request to example.com/cats completes
  axios.get('example.com/cat').then(res.json)
}