44 lines
1.0 KiB
JavaScript
44 lines
1.0 KiB
JavaScript
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const events = new Map();
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class EventBus {
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/**
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* Register an event handler for the given type.
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*
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* @param {String} type Type of event to listen for.
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* @param {Function} handler Function to call in response to given event.
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*/
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on(type, handler) {
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if (events.has(type)) {
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events[type].push(handler);
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} else {
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events[type] = [handler];
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}
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}
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/**
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* Remove an event handler for the given type.
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*
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* @param {String} type Type of event to unregister `handler` from.
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* @param {Function} handler Handler function to remove.
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*/
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off(type, handler) {
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if (events.has(type)) {
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events[type] = events[type].filter((item) => item !== handler);
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}
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}
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/**
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* Invoke all handlers for the given type.
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*
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* @param {String} type The event type to invoke.
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* @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler.
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*/
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emit(type, evt) {
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if (events.has(type)) {
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events[type].slice().map((handler) => handler(evt));
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}
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}
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}
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export default new EventBus();
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