49 lines
1.5 KiB
TypeScript
49 lines
1.5 KiB
TypeScript
import FeatureSource from "./FeatureSource";
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import {UIEventSource} from "../UIEventSource";
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export default class FeatureSourceMerger implements FeatureSource {
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public features: UIEventSource<{ feature: any; freshness: Date }[]> = new UIEventSource<{ feature: any; freshness: Date }[]>([]);
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public readonly name;
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private readonly _sources: FeatureSource[];
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constructor(sources: FeatureSource[]) {
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this._sources = sources;
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this.name = "SourceMerger of (" + sources.map(s => s.name).join(", ") + ")"
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const self = this;
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for (let i = 0; i < sources.length; i++) {
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let source = sources[i];
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source.features.addCallback(() => {
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self.Update();
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});
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}
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this.Update();
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}
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private Update() {
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let all = {}; // Mapping 'id' -> {feature, freshness}
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for (const source of this._sources) {
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if (source?.features?.data === undefined) {
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continue;
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}
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for (const f of source.features.data) {
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const id = f.feature.properties.id;
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const oldV = all[id];
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if (oldV === undefined) {
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all[id] = f;
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} else {
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if (oldV.freshness < f.freshness) {
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all[id] = f;
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}
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}
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}
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}
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const newList = [];
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for (const id in all) {
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newList.push(all[id]);
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}
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this.features.setData(newList);
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}
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} |