Refactoring(uieventsource): introduce 'once'

src/Logic/Osm/OsmPreferences.ts

@@ -34,9 +34,8 @@ export class OsmPreferences {
         this.auth = auth
         this._fakeUser = fakeUser
         this.osmConnection = osmConnection
-        osmConnection.userDetails.addCallbackAndRunD(() => {
+        osmConnection.userDetails.once(() => {
             this.loadBulkPreferences()
-            return true
         })
     }
 

src/Logic/State/UserRelatedState.ts

@@ -389,7 +389,7 @@ export default class UserRelatedState {
      */
     public addUnofficialTheme(themeInfo: MinimalThemeInformation) {
         const pref = this.osmConnection.getPreference("unofficial-theme-" + themeInfo.id)
-        this.osmConnection.isLoggedIn.when(() => pref.set(JSON.stringify(themeInfo)))
+        this.osmConnection.isLoggedIn.once(() => pref.set(JSON.stringify(themeInfo)))
     }
 
     public getUnofficialTheme(id: string): MinimalThemeInformation | undefined {

src/Logic/UIEventSource.ts

@@ -340,8 +340,13 @@ export abstract class Store<T> implements Readable<T> {
 
     public abstract destroy()
 
-    when(callback: () => void, condition?: (v: T) => boolean) {
-        condition ??= (v) => v === true
+    /**
+     * Execute `f` once, but only if the value within is true-ish (or the explicit 'condition' is met)
+     * @param callback
+     * @param condition
+     */
+    public once(callback: () => void, condition?: (v: T) => boolean) {
+        condition ??= (v) => !!v
         this.addCallbackAndRunD((v) => {
             if (condition(v)) {
                 callback()