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