75 lines
3.3 KiB
JavaScript
75 lines
3.3 KiB
JavaScript
var _EventEmitter_listeners;
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import { __classPrivateFieldGet } from "../internal/tslib.mjs";
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export class EventEmitter {
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constructor() {
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_EventEmitter_listeners.set(this, {});
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}
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/**
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* Adds the listener function to the end of the listeners array for the event.
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* No checks are made to see if the listener has already been added. Multiple calls passing
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* the same combination of event and listener will result in the listener being added, and
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* called, multiple times.
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* @returns this, so that calls can be chained
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*/
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on(event, listener) {
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const listeners = __classPrivateFieldGet(this, _EventEmitter_listeners, "f")[event] || (__classPrivateFieldGet(this, _EventEmitter_listeners, "f")[event] = []);
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listeners.push({ listener });
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return this;
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}
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/**
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* Removes the specified listener from the listener array for the event.
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* off() will remove, at most, one instance of a listener from the listener array. If any single
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* listener has been added multiple times to the listener array for the specified event, then
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* off() must be called multiple times to remove each instance.
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* @returns this, so that calls can be chained
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*/
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off(event, listener) {
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const listeners = __classPrivateFieldGet(this, _EventEmitter_listeners, "f")[event];
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if (!listeners)
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return this;
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const index = listeners.findIndex((l) => l.listener === listener);
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if (index >= 0)
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listeners.splice(index, 1);
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return this;
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}
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/**
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* Adds a one-time listener function for the event. The next time the event is triggered,
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* this listener is removed and then invoked.
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* @returns this, so that calls can be chained
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*/
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once(event, listener) {
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const listeners = __classPrivateFieldGet(this, _EventEmitter_listeners, "f")[event] || (__classPrivateFieldGet(this, _EventEmitter_listeners, "f")[event] = []);
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listeners.push({ listener, once: true });
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return this;
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}
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/**
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* This is similar to `.once()`, but returns a Promise that resolves the next time
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* the event is triggered, instead of calling a listener callback.
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* @returns a Promise that resolves the next time given event is triggered,
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* or rejects if an error is emitted. (If you request the 'error' event,
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* returns a promise that resolves with the error).
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*
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* Example:
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*
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* const message = await stream.emitted('message') // rejects if the stream errors
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*/
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emitted(event) {
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return new Promise((resolve, reject) => {
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// TODO: handle errors
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this.once(event, resolve);
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});
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}
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_emit(event, ...args) {
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const listeners = __classPrivateFieldGet(this, _EventEmitter_listeners, "f")[event];
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if (listeners) {
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__classPrivateFieldGet(this, _EventEmitter_listeners, "f")[event] = listeners.filter((l) => !l.once);
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listeners.forEach(({ listener }) => listener(...args));
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}
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}
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_hasListener(event) {
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const listeners = __classPrivateFieldGet(this, _EventEmitter_listeners, "f")[event];
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return listeners && listeners.length > 0;
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}
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}
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_EventEmitter_listeners = new WeakMap();
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//# sourceMappingURL=EventEmitter.mjs.map
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