refactor: derive availableModes from modeSources

static/player/episodes/nav.ts

@@ -61,7 +61,6 @@ export const goToNextEpisode = async (): Promise<void> => {
 
     // update state with new episode data
     state.modeSources = data.mode_sources ?? {};
-    state.availableModes = data.available_modes ?? [];
 
     const backendMode = typeof data.initial_mode === "string" ? data.initial_mode : "";
     const fallback = state.modeSources[backendMode]?.token

static/player/mode.ts

@@ -48,11 +48,6 @@ const alternateModeFor = (mode: string): "sub" | "dub" | null => {
   return null;
 };
 
-const mergeAvailableMode = (mode: string): void => {
-  if (state.availableModes.includes(mode)) return;
-  state.availableModes = [...state.availableModes, mode].sort();
-};
-
 export const hydrateAlternateMode = async (signal?: AbortSignal): Promise<void> => {
   const alternateMode = alternateModeFor(state.currentMode);
   if (!alternateMode) return;
@@ -76,7 +71,6 @@ export const hydrateAlternateMode = async (signal?: AbortSignal): Promise<void>
       ...state.modeSources,
       [alternateMode]: alternateSource,
     };
-    mergeAvailableMode(alternateMode);
 
     updateSubtitleOptions();
     updateQualityOptions();

static/player/state.ts

@@ -11,7 +11,7 @@ export interface PlayerState {
   timeDisplay: HTMLElement;
   durationDisplay: HTMLElement;
   modeSources: Record<string, ModeSource>;
-  availableModes: string[];
+  readonly availableModes: string[];
   currentMode: string;
   modeSwitchedFrom: string;
   currentEpisode: string;
@@ -54,7 +54,9 @@ const createInitialState = (): PlayerState => ({
   timeDisplay: document.createElement("div"),
   durationDisplay: document.createElement("div"),
   modeSources: {},
-  availableModes: [],
+  get availableModes() {
+    return Object.keys(this.modeSources);
+  },
   currentMode: "dub",
   modeSwitchedFrom: "",
   currentEpisode: "1",
@@ -211,8 +213,6 @@ export const initState = (c: HTMLElement): boolean => {
     return out;
   };
 
-  const parseAvailableModes = (v: unknown): string[] => (isStringArray(v) ? v : []);
-
   const parseSegments = (v: unknown): SkipSegment[] => {
     if (!Array.isArray(v)) return [];
     const out: SkipSegment[] = [];
@@ -230,7 +230,6 @@ export const initState = (c: HTMLElement): boolean => {
 
   // mode sources = { sub: { token, subtitles, qualities }, dub: { ... } }
   state.modeSources = parseModeSources(safeJsonUnknown(dataset(c, "modeSources")));
-  state.availableModes = parseAvailableModes(safeJsonUnknown(dataset(c, "availableModes")));
 
   // resolve initial mode: localStorage > backend default > first available > 'dub'
   const backendInitialMode = dataset(c, "initialMode") || "dub";