mapcomplete/Logic/FeatureSource/FeatureSourceMerger.ts

49 lines
No EOL
1.5 KiB
TypeScript

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 }[]>([]);
public readonly name;
private readonly _sources: FeatureSource[];
constructor(sources: FeatureSource[]) {
this._sources = sources;
this.name = "SourceMerger of (" + sources.map(s => s.name).join(", ") + ")"
const self = this;
for (let i = 0; i < sources.length; i++) {
let source = sources[i];
source.features.addCallback(() => {
self.Update();
});
}
this.Update();
}
private Update() {
let all = {}; // Mapping 'id' -> {feature, freshness}
for (const source of this._sources) {
if (source?.features?.data === undefined) {
continue;
}
for (const f of source.features.data) {
const id = f.feature.properties.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);
}
}