fix: replace waitForEvent() by once()

abstract.js

@@ -1,5 +1,8 @@
+'use strict'
+
 const Packet = require('aedes-packet')
-const { PromisifiedPersistence, waitForEvent, getArrayFromStream } = require('./promisified.js')
+const { once } = require('node:events')
+const { PromisifiedPersistence, getArrayFromStream } = require('./promisified.js')
 
 // helper functions
 
@@ -73,7 +76,7 @@ function abstractPersistence (opts) {
       // destroyed while it's still being set up.
       // https://github.com/mcollina/aedes-persistence-redis/issues/41
       if (waitForReady && !instance.ready) {
-        await waitForEvent(instance, 'ready')
+        await once(instance, 'ready')
       }
       t.diagnostic('instance created')
       const prInstance = new PromisifiedPersistence(instance)

promisified.js

@@ -1,3 +1,5 @@
+'use strict'
+
 // promisified versions of the persistence interface
 // to avoid deep callbacks while testing
 
@@ -272,14 +274,6 @@ class PromisifiedPersistence {
 // end of promisified versions ofthis.instance methods
 
 // helper functions
-function waitForEvent (obj, resolveEvt) {
-  return new Promise((resolve, reject) => {
-    obj.once(resolveEvt, () => {
-      resolve()
-    })
-    obj.once('error', reject)
-  })
-}
 
 // stream.toArray() sometimes returns undefined or [undefined] instead of []
 async function getArrayFromStream (stream) {
@@ -294,6 +288,5 @@ async function getArrayFromStream (stream) {
 
 module.exports = {
   PromisifiedPersistence,
-  waitForEvent,
   getArrayFromStream
 }