AVA 4 removing callback support?

[Devwulf]

While going through the AVA docs found here, it says that

AVA 4 removes support for test.cb() and t.end().

Searching in Google about this did not turn up any results, although I didn't search too far. I'm curious, what is the reason for this? What will be the alternatives for callback testing?

[novemberborn]

Yes, it's being removed. Modern APIs tend to use promises, not callbacks, and those are best tested using async/await. Callback tests required a lot of duplication in our type definitions. It didn't seem worth the maintenance cost.

You can use promisify from the built-in util module to wrap a callback-taking API, or the test implementation itself:

import { promisify } from 'node:util'
import test from 'ava'

const withCallback = fn => async t => {
  await promisify(fn)(t)
  t.pass() // There must be at least one passing assertion for the test to pass
}

test('callbackish', withCallback((t, end) => {
  someCallbackThing(end)
})

(I haven't tested this.)

[Devwulf]

Thank you for the answer! I was just wondering why, because I myself don't know the current state of APIs and libraries, and the best practices that go with them.

[joel-chu]

So how are we going to test a socket app?

socket.on('message', function message(msg) {
    // assertion 
})

[sindresorhus]

https://github.com/sindresorhus/p-event or new Promise.