mapcomplete/UI/UIEventSource.ts
2020-07-08 11:23:36 +02:00

53 lines
No EOL
1.1 KiB
TypeScript

export class UIEventSource<T>{
public data : T;
private _callbacks = [];
constructor(data: T) {
this.data = data;
}
public addCallback(callback: ((latestData : T) => void)) {
this._callbacks.push(callback);
return this;
}
public setData(t: T): void {
if (this.data === t) {
return;
}
this.data = t;
this.ping();
}
public ping(): void {
for (const callback of this._callbacks) {
callback(this.data);
}
}
public map<J>(f: ((T) => J),
extraSources : UIEventSource<any>[] = []): UIEventSource<J> {
const self = this;
const update = function () {
newSource.setData(f(self.data));
newSource.ping();
}
this.addCallback(update);
for (const extraSource of extraSources) {
extraSource.addCallback(update);
}
const newSource = new UIEventSource<J>(
f(this.data)
);
return newSource;
}
}