UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2):

This happens when you have promise but forget to .catch() it.

In my case, I tend to forget this with async functions, like:

async function test() {

test() // this can cause the unhandled promise rejection

You can do it globally this way.

process.on('unhandledRejection', (err) => { ... })

I don’t think it’s a good idea to rely on this process.on(..), becasue you have to make sure that you .then().catch() your promises correctly in the first place.