get initial value in initializer

Author: alanjhughes

packages/react-native/React/CoreModules/RCTAppearance.h

@@ -17,4 +17,5 @@ RCT_EXTERN NSString *RCTCurrentOverrideAppearancePreference();
 RCT_EXTERN NSString *RCTColorSchemePreference(UITraitCollection *traitCollection);
 
 @interface RCTAppearance : RCTEventEmitter <RCTBridgeModule>
+- (instancetype)init;
 @end

packages/react-native/React/CoreModules/RCTAppearance.mm

@@ -36,15 +36,6 @@ void RCTOverrideAppearancePreference(NSString *const colorSchemeOverride)
   return sColorSchemeOverride;
 }
 
-static UITraitCollection *getKeyWindowTraitCollection()
-{
-  __block UITraitCollection *traitCollection = nil;
-  RCTUnsafeExecuteOnMainQueueSync(^{
-    traitCollection = RCTSharedApplication().delegate.window.traitCollection;
-  });
-  return traitCollection;
-}
-
 NSString *RCTColorSchemePreference(UITraitCollection *traitCollection)
 {
   static NSDictionary *appearances;
@@ -66,7 +57,6 @@ void RCTOverrideAppearancePreference(NSString *const colorSchemeOverride)
     return RCTAppearanceColorSchemeLight;
   }
 
-  traitCollection = traitCollection ?: getKeyWindowTraitCollection();
   return appearances[@(traitCollection.userInterfaceStyle)] ?: RCTAppearanceColorSchemeLight;
 }
 
@@ -77,6 +67,15 @@ @implementation RCTAppearance {
   NSString *_currentColorScheme;
 }
 
+- (instancetype)init
+{
+  if ((self = [super init])) {
+    UITraitCollection *traitCollection = RCTSharedApplication().delegate.window.traitCollection;
+    _currentColorScheme = RCTColorSchemePreference(traitCollection);
+  }
+  return self;
+}
+
 RCT_EXPORT_MODULE(Appearance)
 
 + (BOOL)requiresMainQueueSetup
@@ -106,9 +105,6 @@ - (dispatch_queue_t)methodQueue
 
 RCT_EXPORT_SYNCHRONOUS_TYPED_METHOD(NSString *, getColorScheme)
 {
-  if (_currentColorScheme == nil) {
-    _currentColorScheme = RCTColorSchemePreference(nil);
-  }
   return _currentColorScheme;
 }