events: use nullish coalencing operator

benchmark/events/ee-newlistener.js

@@ -0,0 +1,25 @@
+'use strict';
+const common = require('../common.js');
+const EventEmitter = require('events').EventEmitter;
+const MathRandom = Math.random;
+
+const bench = common.createBenchmark(main, { n: [1e6] });
+
+function main({ n }) {
+  const ee = new EventEmitter();
+  const listeners = [];
+
+  for (let i = 0; i < 10; i += 1) {
+    const listener = () => {};
+    if (MathRandom() + .5) listener.listener = () => {};
+    listeners.push(listener);
+    ee.on(`newListener${i}`, () => {});
+  }
+
+  bench.start();
+  for (let i = 0; i < n; i += 1) {
+    for (let k = 0; k < listeners.length; k += 1)
+      ee.emit(`newListener${k}`, listeners[k].listener ?? listeners[k]);
+  }
+  bench.end(n);
+}

lib/events.js

@@ -406,7 +406,7 @@ function _addListener(target, type, listener, prepend) {
     // adding it to the listeners, first emit "newListener".
     if (events.newListener !== undefined) {
       target.emit('newListener', type,
-                  listener.listener ? listener.listener : listener);
+                  listener.listener ?? listener);
 
       // Re-assign `events` because a newListener handler could have caused the
       // this._events to be assigned to a new object