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fix: simplify MutationSensitiveArray listener system

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This commit is contained in:
shirakaba
2022-12-17 22:46:07 +09:00
parent 95f9c44441
commit 217cd78114
2 changed files with 9 additions and 29 deletions
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11
packages/core/data/dom-events/dom-event.ts
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@@ -353,16 +353,17 @@ export class DOMEvent implements Event {
// Set a listener to clone the array just before any mutations. // Set a listener to clone the array just before any mutations.
let listenersLazyCopy: ListenerEntry[] = listenersLive; let listenersLazyCopy: ListenerEntry[] = listenersLive;
const doLazyCopy = () => { listenersLive.onMutation = () => (mutation: string, payload?: unknown) => {
console.log(`handleEvent "${data.eventName}": doLazyCopy due to "${mutation}"`, payload);
// Cloning the array via spread syntax is up to 180 nanoseconds // Cloning the array via spread syntax is up to 180 nanoseconds
// faster per run than using Array.prototype.slice(). // faster per run than using Array.prototype.slice().
listenersLazyCopy = [...listenersLive]; listenersLazyCopy = [...listenersLive];
listenersLive.onMutation = null;
}; };
listenersLive.once(doLazyCopy);
// Make sure we remove the listener before we exit the function, // Make sure we clear the callback before we exit the function,
// otherwise we may wastefully clone the array. // otherwise we may wastefully clone the array on future mutations.
const cleanup = () => listenersLive.removeListener(doLazyCopy); const cleanup = () => (listenersLive.onMutation = null);
for (let i = listenersLazyCopy.length - 1; i >= 0; i--) { for (let i = listenersLazyCopy.length - 1; i >= 0; i--) {
const listener = listenersLazyCopy[i]; const listener = listenersLazyCopy[i];

27
packages/core/data/mutation-sensitive-array/index.ts
View File

@@ -8,32 +8,11 @@
* its entire purpose is to be used for performance-sensitive tasks. * its entire purpose is to be used for performance-sensitive tasks.
*/ */
export class MutationSensitiveArray<T> extends Array<T> { export class MutationSensitiveArray<T> extends Array<T> {
private readonly listeners: (() => void)[] = []; onMutation: (() => void) | null = null;
once(listener: () => void): void {
const wrapper = () => {
listener();
this.removeListener(wrapper);
};
this.addListener(wrapper);
}
addListener(listener: () => void): void {
if (!this.listeners.includes(listener)) {
this.listeners.push(listener);
}
}
removeListener(listener: () => void): void {
const index = this.listeners.indexOf(listener);
if (index > -1) {
this.listeners.splice(index, 1);
}
}
private invalidate(): void { private invalidate(): void {
for (const listener of this.listeners) { if (this.onMutation) {
listener(); this.onMutation();
} }
} }