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fix: lazily bind context to removeEventListener callbacks

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shirakaba
2022-12-21 10:24:34 +09:00
parent ab56e114ea
commit 0513789904
1 changed files with 13 additions and 7 deletions
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20
packages/core/data/dom-events/dom-event.ts
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@@ -306,7 +306,13 @@ export class DOMEvent implements Event {
// the static method named `removeEventListener` on the target's class
// allows us to be robust to the possiblity of the case of the target
// overriding it (however unlikely).
const removeGlobalEventListener = (target.constructor as unknown as typeof target).removeEventListener.bind(target.constructor) as Observable['removeEventListener'];
//
// Rather than eagerly binding the context to the function right here,
// we pass the function along with its context to handleEvent() to allow
// binding only once needed - doing this for each of the
// removeEventListener callbacks saves 100 nanoseconds per dispatchTo()
// call.
const removeGlobalEventListener = (target.constructor as unknown as typeof target).removeEventListener as Observable['removeEventListener'];
// Global event handlers are a NativeScript-only concept, so we'll not
// try to add new formal event phases for them (as that could break DOM
@@ -326,7 +332,7 @@ export class DOMEvent implements Event {
// possible.
this.listenersLazyCopy = this.listenersLive = getGlobalEventHandlersPreHandling?.() || emptyArray;
this.handleEvent(data, true, this.CAPTURING_PHASE, removeGlobalEventListener);
this.handleEvent(data, true, this.CAPTURING_PHASE, removeGlobalEventListener, target.constructor);
const eventPath = this.getEventPath(target, 'capture');
@@ -339,7 +345,7 @@ export class DOMEvent implements Event {
this.eventPhase = this.target === this.currentTarget ? this.AT_TARGET : this.CAPTURING_PHASE;
this.listenersLazyCopy = this.listenersLive = currentTarget.getEventList(this.type) || emptyArray;
this.handleEvent(data, false, this.CAPTURING_PHASE, currentTarget.removeEventListener.bind(currentTarget) as Observable['removeEventListener']);
this.handleEvent(data, false, this.CAPTURING_PHASE, currentTarget.removeEventListener, currentTarget);
if (this.propagationState !== EventPropagationState.resume) {
this.resetForRedispatch();
@@ -354,7 +360,7 @@ export class DOMEvent implements Event {
this.eventPhase = this.target === this.currentTarget ? this.AT_TARGET : this.BUBBLING_PHASE;
this.listenersLazyCopy = this.listenersLive = currentTarget.getEventList(this.type) || emptyArray;
this.handleEvent(data, false, this.BUBBLING_PHASE, currentTarget.removeEventListener.bind(currentTarget) as Observable['removeEventListener']);
this.handleEvent(data, false, this.BUBBLING_PHASE, currentTarget.removeEventListener, currentTarget);
if (this.propagationState !== EventPropagationState.resume) {
this.resetForRedispatch();
@@ -375,7 +381,7 @@ export class DOMEvent implements Event {
}
this.listenersLazyCopy = this.listenersLive = getGlobalEventHandlersPostHandling?.() || emptyArray;
this.handleEvent(data, true, this.BUBBLING_PHASE, removeGlobalEventListener);
this.handleEvent(data, true, this.BUBBLING_PHASE, removeGlobalEventListener, target.constructor);
this.resetForRedispatch();
return !this.defaultPrevented;
@@ -383,7 +389,7 @@ export class DOMEvent implements Event {
// Taking multiple params instead of a single property bag saves 250
// nanoseconds per dispatchTo() call.
private handleEvent(data: EventData, isGlobal: boolean, phase: 0 | 1 | 2 | 3, removeEventListener: (eventName: string, callback?: any, thisArg?: any, capture?: boolean) => void) {
private handleEvent(data: EventData, isGlobal: boolean, phase: 0 | 1 | 2 | 3, removeEventListener: (eventName: string, callback?: any, thisArg?: any, capture?: boolean) => void, removeEventListenerContext: unknown) {
// Set a listener to clone the array just before any mutations.
this.listenersLive.onMutation = this.onCurrentListenersMutation.bind(this);
@@ -416,7 +422,7 @@ export class DOMEvent implements Event {
}
if (once) {
removeEventListener(this.type, callback, thisArg, capture);
removeEventListener.call(removeEventListenerContext, this.type, callback, thisArg, capture);
}
// Consistent with the original implementation, we only apply