mapcomplete/Logic/FeatureSource/FeatureSourceMerger.ts

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import FeatureSource from "./FeatureSource";
import {UIEventSource} from "../UIEventSource";
export default class FeatureSourceMerger implements FeatureSource {
public features: UIEventSource<{ feature: any; freshness: Date }[]> = new UIEventSource<{feature: any; freshness: Date}[]>([]);
private readonly _sources: FeatureSource[];
constructor(sources: FeatureSource[]) {
this._sources = sources;
const self = this;
for (const source of sources) {
source.features.addCallback(() => self.Update());
}
}
private Update() {
let all = {}; // Mapping 'id' -> {feature, freshness}
for (const source of this._sources) {
for (const f of source.features.data) {
const id = f.feature.properties.id+f.feature.geometry.type+f.feature._matching_layer_id;
const oldV = all[id];
if(oldV === undefined){
all[id] = f;
}else{
if(oldV.freshness < f.freshness){
all[id]=f;
}
}
}
}
const newList = [];
for (const id in all) {
newList.push(all[id]);
}
this.features.setData(newList);
}
}