Simplify Redux reducer source code

react/features/largeVideo/reducer.js

@@ -3,35 +3,29 @@ import { ReducerRegistry } from '../base/redux';
 
 import { LARGE_VIDEO_PARTICIPANT_CHANGED } from './actionTypes';
 
-const INITIAL_STATE = {
-    participantId: undefined
-};
+ReducerRegistry.register('features/largeVideo', (state = {}, action) => {
+    switch (action.type) {
 
-ReducerRegistry.register(
-    'features/largeVideo',
-    (state = INITIAL_STATE, action) => {
-        switch (action.type) {
-
-        // When conference is joined, we update ID of local participant from
-        // default 'local' to real ID. However, in large video we might have
-        // already selected 'local' as participant on stage. So in this case we
-        // must update ID of participant on stage to match ID in 'participants'
-        // state to avoid additional changes in state and (re)renders.
-        case PARTICIPANT_ID_CHANGED:
-            if (state.participantId === action.oldValue) {
-                return {
-                    ...state,
-                    participantId: action.newValue
-                };
-            }
-            break;
-
-        case LARGE_VIDEO_PARTICIPANT_CHANGED:
+    // When conference is joined, we update ID of local participant from default
+    // 'local' to real ID. However, in large video we might have already
+    // selected 'local' as participant on stage. So in this case we must update
+    // ID of participant on stage to match ID in 'participants' state to avoid
+    // additional changes in state and (re)renders.
+    case PARTICIPANT_ID_CHANGED:
+        if (state.participantId === action.oldValue) {
             return {
                 ...state,
-                participantId: action.participantId
+                participantId: action.newValue
             };
         }
+        break;
 
-        return state;
-    });
+    case LARGE_VIDEO_PARTICIPANT_CHANGED:
+        return {
+            ...state,
+            participantId: action.participantId
+        };
+    }
+
+    return state;
+});