67 lines
2.1 KiB
JavaScript
67 lines
2.1 KiB
JavaScript
/**
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* Copyright 2022 Google LLC.
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* Copyright (c) Microsoft Corporation.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import mitt from 'mitt';
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export class EventEmitter {
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#emitter = mitt();
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on(type, handler) {
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this.#emitter.on(type, handler);
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return this;
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}
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/**
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* Like `on` but the listener will only be fired once and then it will be removed.
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* @param event The event you'd like to listen to
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* @param handler The handler function to run when the event occurs
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* @return `this` to enable chaining method calls.
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*/
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once(event, handler) {
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const onceHandler = (eventData) => {
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handler(eventData);
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this.off(event, onceHandler);
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};
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return this.on(event, onceHandler);
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}
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off(type, handler) {
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this.#emitter.off(type, handler);
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return this;
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}
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/**
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* Emits an event and call any associated listeners.
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*
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* @param event The event to emit.
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* @param eventData Any data to emit with the event.
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* @return `true` if there are any listeners, `false` otherwise.
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*/
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emit(event, eventData) {
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this.#emitter.emit(event, eventData);
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}
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/**
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* Removes all listeners. If given an event argument, it will remove only
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* listeners for that event.
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* @param event - the event to remove listeners for.
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* @returns `this` to enable you to chain method calls.
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*/
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removeAllListeners(event) {
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if (event) {
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this.#emitter.all.delete(event);
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}
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else {
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this.#emitter.all.clear();
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}
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return this;
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}
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}
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//# sourceMappingURL=EventEmitter.js.map
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