50 lines
1.7 KiB
TypeScript
50 lines
1.7 KiB
TypeScript
/// Given a feature source, calculates a list of OSM-contributors who mapped the latest versions
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import { Store, UIEventSource } from "./UIEventSource"
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import { BBox } from "./BBox"
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import GeoIndexedStore from "./FeatureSource/Actors/GeoIndexedStore"
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export default class ContributorCount {
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public readonly Contributors: UIEventSource<Map<string, number>> = new UIEventSource<
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Map<string, number>
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>(new Map<string, number>())
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private readonly perLayer: ReadonlyMap<string, GeoIndexedStore>
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private lastUpdate: Date = undefined
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constructor(state: {
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mapProperties: { bounds: Store<BBox> }
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dataIsLoading: Store<boolean>
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perLayer: ReadonlyMap<string, GeoIndexedStore>
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}) {
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this.perLayer = state.perLayer
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const self = this
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state.mapProperties.bounds.mapD(
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(bbox) => {
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self.update(bbox)
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},
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[state.dataIsLoading]
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)
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}
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private update(bbox: BBox) {
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const now = new Date()
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if (
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this.lastUpdate !== undefined &&
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now.getTime() - this.lastUpdate.getTime() < 1000 * 60
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) {
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return
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}
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this.lastUpdate = now
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const featuresList = [].concat(
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Array.from(this.perLayer.values()).map((fs) => fs.GetFeaturesWithin(bbox))
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)
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const hist = new Map<string, number>()
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for (const list of featuresList) {
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for (const feature of list) {
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const contributor = feature.properties["_last_edit:contributor"]
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const count = hist.get(contributor) ?? 0
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hist.set(contributor, count + 1)
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}
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}
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this.Contributors.setData(hist)
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}
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}
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