perf: reduce iterations and allocations (#2481)

* Object.keys and Object.values were used in some for loops,
which increased allocations and memory pressure unnecessarily.

frontend/src/components/Playback/TrackList.vue

@@ -32,7 +32,7 @@
     <tbody>
       <template v-for="(tracksOnDisc, discNumber) in tracksPerDisc">
         <tr
-          v-if="Object.keys(tracksPerDisc).length > 1"
+          v-if="hasMultipleDiscs"
           :key="discNumber"
           class="disc-header">
           <td
@@ -137,6 +137,19 @@ const { data: tracks } = await useBaseItem(getItemsApi, 'getItems')(() => ({
 }));
 
 const tracksPerDisc = computed(() => Object.groupBy(tracks.value, ({ ParentIndexNumber }) => ParentIndexNumber!));
+const hasMultipleDiscs = computed(() => {
+  let loops = 0;
+
+  for (const _ in tracksPerDisc.value) {
+    loops++;
+
+    if (loops > 1) {
+      return true;
+    }
+  }
+
+  return false;
+});
 
 /**
  * Check if a given BaseItemDto is playing

frontend/src/plugins/workers/generic/subtitles.ts

@@ -35,12 +35,12 @@ function replaceTags(input: string, tagMap: TagMap) {
   let formattedText = input;
 
   // Iterate through tag mappings
-  for (const [htmlTag, markdownTag] of Object.entries(tagMap)) {
+  for (const htmlTag in tagMap) {
     const escapedHtmlTag = htmlTag.replaceAll('\\', '\\\\');
     const regex = new RegExp(escapedHtmlTag, 'gi');
 
     formattedText = formattedText.replace(regex, (_, p1: string) => {
-      return markdownTag.replace('$1', p1.trim());
+      return tagMap[htmlTag].replace('$1', p1.trim());
     });
   }
 

frontend/src/store/playback-manager.ts

@@ -1133,12 +1133,12 @@ class PlaybackManagerStore extends CommonStore<PlaybackManagerState> {
             }
           };
 
-          for (const [action, handler] of Object.entries(actionHandlers)) {
+          for (const action in actionHandlers) {
             try {
               window.navigator.mediaSession.setActionHandler(
                 action as MediaSessionAction,
                 /* eslint-disable-next-line unicorn/no-null */
-                add ? handler : null
+                add ? actionHandlers[action as keyof typeof actionHandlers] ?? null : null
               );
             } catch {
               console.error(

packages/configs/eslint/rules/typescript-vue.ts

@@ -7,7 +7,6 @@ import eslintImportX from 'eslint-plugin-import-x';
 // @ts-expect-error - No types available
 import vueScopedCSS from 'eslint-plugin-vue-scoped-css';
 import css from 'eslint-plugin-css';
-// @ts-expect-error - No types available
 import vue from 'eslint-plugin-vue';
 // @ts-expect-error - No types available
 import promise from 'eslint-plugin-promise';
@@ -94,6 +93,18 @@ const common = [
       }],
       '@typescript-eslint/no-confusing-void-expression': ['error', { ignoreArrowShorthand: true }],
       '@typescript-eslint/no-empty-object-type': ['error', { allowInterfaces: 'with-single-extends' }],
+      '@typescript-eslint/no-unused-vars': [
+        'error',
+        {
+          args: 'all',
+          argsIgnorePattern: '^_',
+          caughtErrors: 'all',
+          caughtErrorsIgnorePattern: '^_',
+          destructuredArrayIgnorePattern: '^_',
+          varsIgnorePattern: '^_',
+          ignoreRestSiblings: true
+        }
+      ],
       'vue/return-in-computed-property': 'off'
     }
   },