events: refactor to use optional chaining

Lxxyx · danielleadams · commit 3fa470a3c930 · 2021-01-12T07:11:40.000-05:00
Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com> PR-URL: #36763 Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
diff --git 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) => {
@@ -765,7 +765,7 @@ 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);
@@ -780,9 +780,9 @@ 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
@@ -95,7 +95,7 @@ class Event {
 this[kDefaultPrevented] = false;
 this[kTimestamp] = lazyNow();
 this[kPropagationStopped] = false;
- if (options != null && options[kTrustEvent]) {
+ if (options?.[kTrustEvent]) {
 isTrustedSet.add(this);
 }
 
@@ -185,7 +185,7 @@ 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;
 }
 }
@@ -340,10 +340,7 @@ 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)
@@ -555,9 +552,7 @@ 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;
 }
 
@@ -586,7 +581,7 @@ 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) {

-Original file line number
+Diff line change
 this._maxListeners=this._maxListeners||undefined;
 -if(opts&&opts.captureRejections){
 +if(opts?.captureRejections){
 if(typeofopts.captureRejections!=='boolean'){
 thrownewERR_INVALID_ARG_TYPE('options.captureRejections',
 'boolean',opts.captureRejections);
+}
 asyncfunctiononce(emitter,name,options={}){
 -constsignal=options ? options.signal : undefined;
 +constsignal=options?.signal;
 validateAbortSignal(signal,'options.signal');
 -if(signal&&signal.aborted)
 +if(signal?.aborted)
 throwlazyDOMException('The operation was aborted','AbortError');
 returnnewPromise((resolve,reject)=>{
 consterrorListener=(err)=>{
 functioneventTargetAgnosticAddListener(emitter,name,listener,flags){
 if(typeofemitter.on==='function'){
 -if(flags&&flags.once){
 +if(flags?.once){
 emitter.once(name,listener);
 }else{
 emitter.on(name,listener);
+}
 functionon(emitter,event,options){
 -const{signal }={ ...options};
 +constsignal=options?.signal;
 validateAbortSignal(signal,'options.signal');
 -if(signal&&signal.aborted){
 +if(signal?.aborted){
 throwlazyDOMException('The operation was aborted','AbortError');
+}
-Original file line number
+Diff line change
 this[kDefaultPrevented]=false;
 this[kTimestamp]=lazyNow();
 this[kPropagationStopped]=false;
 -if(options!=null&&options[kTrustEvent]){
 +if(options?.[kTrustEvent]){
 isTrustedSet.add(this);
+}
 classNodeCustomEventextendsEvent{
 constructor(type,options){
 super(type,options);
 -if(options&&options.detail){
 +if(options?.detail){
 this.detail=options.detail;
+}
+}
 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);
 -constcapture=options!=null&&options.capture===true;
 +constcapture=options?.capture===true;
 constroot=this[kEvents].get(type);
 if(root===undefined||root.next===undefined)
 functionshouldAddListener(listener){
 if(typeoflistener==='function'||
 -(listener!=null&&
 -typeoflistener==='object'&&
 -typeoflistener.handleEvent==='function')){
 +typeoflistener?.handleEvent==='function'){
 returntrue;
+}
 // It stands in its current implementation as a compromise.
 // Ref: https://github.com/nodejs/node/pull/33661
 functionisEventTarget(obj){
 -returnobj&&obj.constructor&&obj.constructor[kIsEventTarget];
 +returnobj?.constructor?.[kIsEventTarget];
+}
 functionaddCatch(that,promise,event){