From 18e5c0f3e2e9cd68153ab34a5639e195ae615ee4 Mon Sep 17 00:00:00 2001
From: ZiJian Liu <Lxxyxzj@gmail.com>
Date: Mon, 4 Jan 2021 13:50:51 +0800
Subject: [PATCH] events: refactor to use optional chaining

Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/36763
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
---
 lib/events.js                | 12 ++++++------
 lib/internal/event_target.js | 15 +++++----------
 2 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/lib/events.js b/lib/events.js
index 9e60a1946ad7b1..18500888251b87 100644
--- a/lib/events.js
+++ b/lib/events.js
@@ -203,7 +203,7 @@ EventEmitter.init = function(opts) {
   this._maxListeners = this._maxListeners || undefined;
 
 
-  if (opts && opts.captureRejections) {
+  if (opts?.captureRejections) {
     if (typeof opts.captureRejections !== 'boolean') {
       throw new ERR_INVALID_ARG_TYPE('options.captureRejections',
                                      'boolean', opts.captureRejections);
@@ -709,9 +709,9 @@ function getEventListeners(emitterOrTarget, type) {
 }
 
 async function once(emitter, name, options = {}) {
-  const signal = options ? options.signal : undefined;
+  const signal = options?.signal;
   validateAbortSignal(signal, 'options.signal');
-  if (signal && signal.aborted)
+  if (signal?.aborted)
     throw lazyDOMException('The operation was aborted', 'AbortError');
   return new Promise((resolve, reject) => {
     const errorListener = (err) => {
@@ -791,7 +791,7 @@ function eventTargetAgnosticRemoveListener(emitter, name, listener, flags) {
 
 function eventTargetAgnosticAddListener(emitter, name, listener, flags) {
   if (typeof emitter.on === 'function') {
-    if (flags && flags.once) {
+    if (flags?.once) {
       emitter.once(name, listener);
     } else {
       emitter.on(name, listener);
@@ -806,9 +806,9 @@ function eventTargetAgnosticAddListener(emitter, name, listener, flags) {
 }
 
 function on(emitter, event, options) {
-  const { signal } = { ...options };
+  const signal = options?.signal;
   validateAbortSignal(signal, 'options.signal');
-  if (signal && signal.aborted) {
+  if (signal?.aborted) {
     throw lazyDOMException('The operation was aborted', 'AbortError');
   }
 
diff --git a/lib/internal/event_target.js b/lib/internal/event_target.js
index b51bf836c810f4..8117b96a2d40a4 100644
--- a/lib/internal/event_target.js
+++ b/lib/internal/event_target.js
@@ -93,7 +93,7 @@ class Event {
     this[kDefaultPrevented] = false;
     this[kTimestamp] = lazyNow();
     this[kPropagationStopped] = false;
-    if (options != null && options[kTrustEvent]) {
+    if (options?.[kTrustEvent]) {
       isTrustedSet.add(this);
     }
 
@@ -183,7 +183,7 @@ ObjectDefineProperty(Event.prototype, SymbolToStringTag, {
 class NodeCustomEvent extends Event {
   constructor(type, options) {
     super(type, options);
-    if (options && options.detail) {
+    if (options?.detail) {
       this.detail = options.detail;
     }
   }
@@ -323,10 +323,7 @@ class EventTarget {
       return;
 
     type = String(type);
-    // TODO(@jasnell): If it's determined this cannot be backported
-    // to 12.x, then this can be simplified to:
-    //   const capture = Boolean(options?.capture);
-    const capture = options != null && options.capture === true;
+    const capture = options?.capture === true;
 
     const root = this[kEvents].get(type);
     if (root === undefined || root.next === undefined)
@@ -532,9 +529,7 @@ ObjectDefineProperties(NodeEventTarget.prototype, {
 
 function shouldAddListener(listener) {
   if (typeof listener === 'function' ||
-      (listener != null &&
-       typeof listener === 'object' &&
-       typeof listener.handleEvent === 'function')) {
+      typeof listener?.handleEvent === 'function') {
     return true;
   }
 
@@ -562,7 +557,7 @@ function validateEventListenerOptions(options) {
 // It stands in its current implementation as a compromise.
 // Ref: https://github.com/nodejs/node/pull/33661
 function isEventTarget(obj) {
-  return obj && obj.constructor && obj.constructor[kIsEventTarget];
+  return obj?.constructor?.[kIsEventTarget];
 }
 
 function addCatch(that, promise, event) {