mapcomplete/Logic/FeatureSource/RememberingSource.ts

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TypeScript

/**
* Every previously added point is remembered, but new points are added
*/
import FeatureSource from "./FeatureSource";
import {UIEventSource} from "../UIEventSource";
export default class RememberingSource implements FeatureSource{
features: UIEventSource<{feature: any, freshness: Date}[]> = new UIEventSource<{feature: any, freshness: Date}[]>([]);
constructor(source: FeatureSource) {
const self = this;
source.features.addCallbackAndRun(features => {
if(features === undefined){
return;
}
const ids = new Set<string>( features.map(f => f.feature.properties.id+f.feature.geometry.type));
const newList = features.concat(
self.features.data.filter(old => !ids.has(old.feature.properties.id+old.feature.geometry.type))
)
self.features.setData(newList);
})
}
}