28 lines
918 B
TypeScript
28 lines
918 B
TypeScript
class EventEmitter<T> {
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private handlers: { [eventName in keyof T]?: ((value: T[eventName]) => void)[] }
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constructor() {
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this.handlers = {}
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}
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emit<K extends keyof T>(event: K, value: T[K]): void {
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this.handlers[event]?.forEach(h => h(value));
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}
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addHandler<K extends keyof T>(event: K, handler: (value: T[K]) => void): void {
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if(!this.handlers[event]) {
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this.handlers[event] = [handler];
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} else {
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this.handlers[event].push(handler);
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}
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}
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}
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const emitter = new EventEmitter<{ numberChange: number, stringChange: string }>();
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emitter.addHandler("numberChange", n => console.log("New number value is: ", n));
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emitter.addHandler("stringChange", s => console.log("New string value is: ", s));
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emitter.emit("numberChange", 1);
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emitter.emit("stringChange", "3");
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emitter.emit("numberChange", "1");
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emitter.emit("stringChange", 3);
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