34 lines
1.3 KiB
TypeScript
34 lines
1.3 KiB
TypeScript
/**
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* Every previously added point is remembered, but new points are added.
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* Data coming from upstream will always overwrite a previous value
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*/
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import FeatureSource, { Tiled } from "../FeatureSource"
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import { Store, UIEventSource } from "../../UIEventSource"
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import { BBox } from "../../BBox"
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import { Feature } from "geojson"
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export default class RememberingSource implements FeatureSource, Tiled {
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public readonly features: Store<Feature[]>
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public readonly tileIndex: number
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public readonly bbox: BBox
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constructor(source: FeatureSource & Tiled) {
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const self = this
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this.tileIndex = source.tileIndex
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this.bbox = source.bbox
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const empty = []
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const featureSource = new UIEventSource<Feature[]>(empty)
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this.features = featureSource
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source.features.addCallbackAndRunD((features) => {
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const oldFeatures = self.features?.data ?? empty
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// Then new ids
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const ids = new Set<string>(features.map((f) => f.properties.id + f.geometry.type))
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// the old data
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const oldData = oldFeatures.filter(
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(old) => !ids.has(old.feature.properties.id + old.feature.geometry.type)
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)
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featureSource.setData([...features, ...oldData])
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})
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}
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}
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