19 lines
448 B
JavaScript
19 lines
448 B
JavaScript
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export class EventEmitter {
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constructor() {
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this._events = Object.create(null)
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}
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on(type, fn) {
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(this._events[type] || (this._events[type] = [])).push(fn)
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}
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emit(type, ...args) {
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(this._events[type] || []).forEach(fn => fn(...args))
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}
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off(type, fn) {
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if (!fn) this._events[type] = []
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else {
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const idx = (this._events[type] || []).indexOf(fn)
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if (idx > -1) this._events[type].splice(idx, 1)
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}
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}
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}
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