Core: improve typing of mapD

src/Logic/UIEventSource.ts

@@ -31,7 +31,7 @@ export class Stores {
      * @param promise
      * @constructor
      */
-    public static FromPromise<T>(promise: Promise<T>): Store<T> {
+    public static FromPromise<T>(promise: Promise<T>): Store<T | undefined> {
         const src = new UIEventSource<T>(undefined)
         promise?.then((d) => src.setData(d))
         promise?.catch((err) => console.warn("Promise failed:", err))
@@ -97,7 +97,7 @@ export abstract class Store<T> implements Readable<T> {
     abstract map<J>(f: (t: T) => J): Store<J>
     abstract map<J>(f: (t: T) => J, extraStoresToWatch: Store<any>[]): Store<J>
 
-    public mapD<J>(f: (t: T) => J, extraStoresToWatch?: Store<any>[]): Store<J> {
+    public mapD<J>(f: (t: Exclude<T, undefined | null>) => J, extraStoresToWatch?: Store<any>[]): Store<J> {
         return this.map((t) => {
             if (t === undefined) {
                 return undefined
@@ -105,7 +105,7 @@ export abstract class Store<T> implements Readable<T> {
             if (t === null) {
                 return null
             }
-            return f(t)
+            return f(<Exclude<T, undefined | null>> t)
         }, extraStoresToWatch)
     }
 
@@ -603,7 +603,7 @@ export class UIEventSource<T> extends Store<T> implements Writable<T> {
      */
     public static FromPromiseWithErr<T>(
         promise: Promise<T>
-    ): UIEventSource<{ success: T } | { error: any }> {
+    ): UIEventSource<{ success: T } | { error: any } | undefined> {
         const src = new UIEventSource<{ success: T } | { error: any }>(undefined)
         promise?.then((d) => src.setData({ success: d }))
         promise?.catch((err) => src.setData({ error: err }))
@@ -771,18 +771,21 @@ export class UIEventSource<T> extends Store<T> implements Writable<T> {
      * Monoidal map which results in a read-only store. 'undefined' is passed 'as is'
      * Given a function 'f', will construct a new UIEventSource where the contents will always be "f(this.data)'
      */
-    public mapD<J>(f: (t: T) => J, extraSources: Store<any>[] = []): Store<J | undefined> {
+    public mapD<J>(f: (t: Exclude<T, undefined | null>) => J, extraSources: Store<any>[] = []): Store<J | undefined> {
         return new MappedStore(
             this,
             (t) => {
                 if (t === undefined) {
                     return undefined
                 }
-                return f(t)
+                if (t === null) {
+                    return null
+                }
+                return f(<Exclude<T, undefined | null>> t)
             },
             extraSources,
             this._callbacks,
-            this.data === undefined ? undefined : f(this.data)
+            (this.data === undefined || this.data === null) ?(<undefined | null> this.data) : f(<any> this.data)
         )
     }
 

src/Logic/Web/NearbyImagesSearch.ts

@@ -40,15 +40,26 @@ export interface P4CPicture {
 export default class NearbyImagesSearch {
     public static readonly services = ["mapillary", "flickr", "kartaview", "wikicommons"] as const
     public static readonly apiUrls = ["https://api.flickr.com"]
-    private readonly individualStores: Store<{ images: P4CPicture[]; beforeFilter: number }>[]
+    private readonly individualStores: Store<{ images: P4CPicture[]; beforeFilter: number } | undefined>[]
     private readonly _store: UIEventSource<P4CPicture[]> = new UIEventSource<P4CPicture[]>([])
     public readonly store: Store<P4CPicture[]> = this._store
+    public readonly allDone: Store<boolean>
     private readonly _options: NearbyImageOptions
 
     constructor(options: NearbyImageOptions, features: IndexedFeatureSource) {
         this.individualStores = NearbyImagesSearch.services.map((s) =>
             NearbyImagesSearch.buildPictureFetcher(options, s)
         )
+
+        const allDone = new UIEventSource(false)
+        this.allDone = allDone
+        const self = this
+        function updateAllDone(){
+            const stillRunning = self.individualStores.some(store => store.data === undefined)
+            allDone.setData(!stillRunning)
+        }
+        self.individualStores.forEach(s => s.addCallback(_ => updateAllDone()))
+
         this._options = options
         if (features !== undefined) {
             const osmImages = new ImagesInLoadedDataFetcher(features).fetchAround({
@@ -93,13 +104,17 @@ export default class NearbyImagesSearch {
     private static buildPictureFetcher(
         options: NearbyImageOptions,
         fetcher: P4CService
-    ): Store<{ images: P4CPicture[]; beforeFilter: number }> {
+    ): Store<{ images: P4CPicture[]; beforeFilter: number } | null | undefined> {
-        const p4cStore = Stores.FromPromise<P4CPicture[]>(
+        const p4cStore = Stores.FromPromiseWithErr<P4CPicture[]>(
             NearbyImagesSearch.fetchImages(options, fetcher)
         )
         const searchRadius = options.searchRadius ?? 100
-        return p4cStore.map(
+        return p4cStore.mapD(
-            (images) => {
+            (imagesState) => {
+                if(imagesState["error"]){
+                    return null
+                }
+                let images = imagesState["success"]
                 if (images === undefined) {
                     return undefined
                 }