Created
December 12, 2018 08:00
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Simple Typescript Event Bus
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| interface Subscription<T> { | |
| id: number, | |
| type: new () => T | |
| fn: (event:T)=>any | |
| } | |
| class Bus { | |
| private seq:number = 0; | |
| private subscribers:Map<string,Array<Subscription<any>>> = new Map(); | |
| public subscribe<T>(type: new () => T,callback:(event:T)=>any):Subscription<T>{ | |
| const key = new type().constructor.name; | |
| if(!this.subscribers.has(key)){ | |
| this.subscribers.set(key,[]) | |
| } | |
| const subscription = { | |
| id:++this.seq, | |
| fn: callback, | |
| type, | |
| }; | |
| (this.subscribers.get(key) as Array<Subscription<T>>).push(subscription); | |
| return subscription; | |
| } | |
| public emit<T>(event:T){ | |
| const s = this.subscribers.get(event.constructor.name); | |
| if(!s){ | |
| return; | |
| } | |
| s.forEach((subscription)=>{ | |
| subscription.fn(event); | |
| }) | |
| } | |
| public once<T>(type: new () => T,callback:(event:T)=>any){ | |
| let subscription:Subscription<T>; | |
| subscription = this.subscribe(type,(T)=>{ | |
| this.unsubscribe(subscription); | |
| callback(T); | |
| }) | |
| } | |
| public unsubscribe<T>(subscription: Subscription<T>){ | |
| const event = new subscription.type(); | |
| const key = event.constructor.name; | |
| const subs = this.subscribers.get(key); | |
| if (subs){ | |
| subs.splice(subs.findIndex((e:Subscription<T>)=>e.id === subscription.id),1); | |
| } | |
| } | |
| } | |
| export default new Bus(); |
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