[ReactNative] Use RCTNullIfNill and (id)kCFNull

Summary:
@public

Use consistent `null` handling:

`value || null`                ->  `RCTNullIfNil(value)`
`value == null ? nil : value`  ->  `RCTNilIfNull(value)`
`[NSNull null]`                ->  `(id)kCFNull`

Test Plan: The tests should be enough.

Examples/UIExplorer/UIExplorerUnitTests/RCTContextExecutorTests.m

@@ -57,7 +57,7 @@ static uint64_t _get_time_nanoseconds(void)
 
   JSContextGroupRef group = JSContextGroupCreate();
   JSGlobalContextRef context = JSGlobalContextCreateInGroup(group, NULL);
-  id message = @[@[@1, @2, @3, @4], @[@{@"a": @1}, @{@"b": @2}], [NSNull null]];
+  id message = @[@[@1, @2, @3, @4], @[@{@"a": @1}, @{@"b": @2}], (id)kCFNull];
   NSString *code = RCTJSONStringify(message, NULL);
   JSStringRef script = JSStringCreateWithCFString((__bridge CFStringRef)code);
   JSValueRef error = NULL;

Examples/UIExplorer/UIExplorerUnitTests/RCTConvert_NSURLTests.m

@@ -28,7 +28,7 @@ TEST_PATH(name, _input, [[[NSBundle mainBundle] bundlePath] stringByAppendingPat
 
 // Basic tests
 TEST_URL(basic, @"http://example.com", @"http://example.com")
-TEST_URL(null, [NSNull null], nil)
+TEST_URL(null, (id)kCFNull, nil)
 
 // Local files
 TEST_PATH(fileURL, @"file:///blah/hello.jsbundle", @"/blah/hello.jsbundle")

Libraries/ActionSheetIOS/RCTActionSheetManager.m

@@ -10,6 +10,7 @@
 #import "RCTActionSheetManager.h"
 
 #import "RCTLog.h"
+#import "RCTUtils.h"
 
 @interface RCTActionSheetManager () <UIActionSheetDelegate>
 
@@ -90,7 +91,7 @@ RCT_EXPORT_METHOD(showShareActionSheetWithOptions:(NSDictionary *)options
       if (activityError) {
         failureCallback(@[[activityError localizedDescription]]);
       } else {
-        successCallback(@[@(completed), (activityType ?: [NSNull null])]);
+        successCallback(@[@(completed), RCTNullIfNil(activityType)]);
       }
     };
   } else {
@@ -100,7 +101,7 @@ RCT_EXPORT_METHOD(showShareActionSheetWithOptions:(NSDictionary *)options
     if (![UIActivityViewController instancesRespondToSelector:@selector(completionWithItemsHandler)]) {
       // Legacy iOS 7 implementation
       share.completionHandler = ^(NSString *activityType, BOOL completed) {
-        successCallback(@[@(completed), (activityType ?: [NSNull null])]);
+        successCallback(@[@(completed), RCTNullIfNil(activityType)]);
       };
     } else
 
@@ -109,7 +110,7 @@ RCT_EXPORT_METHOD(showShareActionSheetWithOptions:(NSDictionary *)options
     {
       // iOS 8 version
       share.completionWithItemsHandler = ^(NSString *activityType, BOOL completed, NSArray *returnedItems, NSError *activityError) {
-        successCallback(@[@(completed), (activityType ?: [NSNull null])]);
+        successCallback(@[@(completed), RCTNullIfNil(activityType)]);
       };
     }
   }

Libraries/LinkingIOS/RCTLinkingManager.m

@@ -11,6 +11,7 @@
 
 #import "RCTBridge.h"
 #import "RCTEventDispatcher.h"
+#import "RCTUtils.h"
 
 NSString *const RCTOpenURLNotification = @"RCTOpenURLNotification";
 
@@ -76,7 +77,7 @@ RCT_EXPORT_METHOD(canOpenURL:(NSURL *)URL
 - (NSDictionary *)constantsToExport
 {
   NSURL *initialURL = _bridge.launchOptions[UIApplicationLaunchOptionsURLKey];
-  return @{@"initialURL": [initialURL absoluteString] ?: [NSNull null]};
+  return @{@"initialURL": RCTNullIfNil([initialURL absoluteString])};
 }
 
 @end

Libraries/Network/RCTDataManager.m

@@ -436,7 +436,7 @@ RCT_EXPORT_MODULE()
 
     NSArray *responseJSON = @[
       request.requestID,
-      error.localizedDescription ?: [NSNull null],
+      RCTNullIfNil(error.localizedDescription),
     ];
 
     [_bridge.eventDispatcher sendDeviceEventWithName:@"didCompleteNetworkResponse"

Libraries/PushNotificationIOS/RCTPushNotificationManager.m

@@ -11,6 +11,7 @@
 
 #import "RCTBridge.h"
 #import "RCTEventDispatcher.h"
+#import "RCTUtils.h"
 
 #if __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_8_0
 
@@ -172,7 +173,7 @@ RCT_EXPORT_METHOD(checkPermissions:(RCTResponseSenderBlock)callback)
 - (NSDictionary *)constantsToExport
 {
   return @{
-    @"initialNotification": _initialNotification ?: [NSNull null]
+    @"initialNotification": RCTNullIfNil(_initialNotification),
   };
 }
 

Libraries/WebSocket/RCTWebSocketManager.m

@@ -13,6 +13,7 @@
 #import "RCTEventDispatcher.h"
 #import "RCTSRWebSocket.h"
 #import "RCTSparseArray.h"
+#import "RCTUtils.h"
 
 @implementation RCTSRWebSocket (React)
 
@@ -107,7 +108,7 @@ RCT_EXPORT_METHOD(close:(NSNumber *)socketID)
 {
   [_bridge.eventDispatcher sendDeviceEventWithName:@"websocketClosed" body:@{
     @"code": @(code),
-    @"reason": reason ? reason : [NSNull null],
+    @"reason": RCTNullIfNil(reason),
     @"clean": @(wasClean),
     @"id": webSocket.reactTag
   }];

React/Base/RCTBridge.m

@@ -449,7 +449,7 @@ case _value: { \
   // Set arguments
   NSUInteger index = 0;
   for (id json in arguments) {
-    id arg = (json == [NSNull null]) ? nil : json;
+    id arg = RCTNilIfNull(json);
     void (^block)(RCTBridge *, NSNumber *, NSInvocation *, NSUInteger, id) = _argumentBlocks[index];
     block(bridge, context, invocation, index + 2, arg);
     index++;
@@ -1012,7 +1012,7 @@ RCT_INNER_BRIDGE_ONLY(_invokeAndProcessModule:(NSString *)module method:(NSStrin
       if (queue) {
         _queuesByID[moduleID] = queue;
       } else {
-        _queuesByID[moduleID] = [NSNull null];
+        _queuesByID[moduleID] = (id)kCFNull;
       }
     }
 
@@ -1266,8 +1266,8 @@ RCT_INNER_BRIDGE_ONLY(_invokeAndProcessModule:(NSString *)module method:(NSStrin
                                context:context
                               callback:^(id json, NSError *error) {
                                 RCTProfileEndEvent(@"FetchApplicationScriptCallbacks", @"js_call,init", @{
-                                  @"json": json ?: [NSNull null],
+                                  @"json": RCTNullIfNil(json),
-                                  @"error": error ?: [NSNull null],
+                                  @"error": RCTNullIfNil(error),
                                 });
 
                                 [self _handleBuffer:json context:context];
@@ -1293,7 +1293,7 @@ RCT_INNER_BRIDGE_ONLY(_invokeAndProcessModule:(NSString *)module method:(NSStrin
     queue = _queuesByID[moduleID];
   }
 
-  if (queue == [NSNull null]) {
+  if (queue == (id)kCFNull) {
     [_javaScriptExecutor executeBlockOnJavaScriptQueue:block];
   } else {
     dispatch_async(queue ?: _methodQueue, block);
@@ -1509,7 +1509,7 @@ RCT_INNER_BRIDGE_ONLY(_invokeAndProcessModule:(NSString *)module method:(NSStrin
     @"module": method.moduleClassName,
     @"method": method.JSMethodName,
     @"selector": NSStringFromSelector(method.selector),
-    @"args": RCTJSONStringify(params ?: [NSNull null], NULL),
+    @"args": RCTJSONStringify(RCTNullIfNil(params), NULL),
   });
 
   return YES;

React/Base/RCTConvert.m

@@ -54,7 +54,7 @@ RCT_CONVERTER(NSString *, NSString, description)
       RCTLogConvertError(json, "a number");
     }
     return number;
-  } else if (json && json != [NSNull null]) {
+  } else if (json && json != (id)kCFNull) {
     RCTLogConvertError(json, "a number");
   }
   return nil;
@@ -141,7 +141,7 @@ RCT_CONVERTER(NSString *, NSString, description)
                   "Expected format: YYYY-MM-DD'T'HH:mm:ss.sssZ", json);
     }
     return date;
-  } else if (json && json != [NSNull null]) {
+  } else if (json && json != (id)kCFNull) {
     RCTLogConvertError(json, "a date");
   }
   return nil;

React/Base/RCTTouchHandler.m

@@ -107,8 +107,8 @@ typedef NS_ENUM(NSInteger, RCTTouchEventType) {
     NSMutableDictionary *reactTouch = [[NSMutableDictionary alloc] initWithCapacity:9];
     reactTouch[@"target"] = reactTag;
     reactTouch[@"identifier"] = @(touchID);
-    reactTouch[@"touches"] = [NSNull null];        // We hijack this touchObj to serve both as an event
+    reactTouch[@"touches"] = (id)kCFNull;        // We hijack this touchObj to serve both as an event
-    reactTouch[@"changedTouches"] = [NSNull null]; // and as a Touch object, so making this JIT friendly.
+    reactTouch[@"changedTouches"] = (id)kCFNull; // and as a Touch object, so making this JIT friendly.
 
     // Add to arrays
     [_touchViews addObject:targetView];

React/Executors/RCTContextExecutor.m

@@ -137,7 +137,7 @@ static JSValueRef RCTConsoleProfile(JSContextRef context, JSObjectRef object, JS
     profileName = [NSString stringWithFormat:@"Profile %d", profileCounter++];
   }
 
-  id profileInfo = [NSNull null];
+  id profileInfo = (id)kCFNull;
   if (argumentCount > 1 && !JSValueIsUndefined(context, arguments[1])) {
     profileInfo = @[RCTJSValueToNSString(context, arguments[1])];
   }

React/Modules/RCTAsyncLocalStorage.m

@@ -164,14 +164,14 @@ RCT_EXPORT_MODULE()
     return errorOut;
   }
   id value = [self _getValueForKey:key errorOut:&errorOut];
-  [result addObject:@[key, value ?: [NSNull null]]]; // Insert null if missing or failure.
+  [result addObject:@[key, RCTNullIfNil(value)]]; // Insert null if missing or failure.
   return errorOut;
 }
 
 - (NSString *)_getValueForKey:(NSString *)key errorOut:(NSDictionary **)errorOut
 {
   id value = _manifest[key]; // nil means missing, null means there is a data file, anything else is an inline value.
-  if (value == [NSNull null]) {
+  if (value == (id)kCFNull) {
     NSString *filePath = [self _filePathForKey:key];
     value = RCTReadFile(filePath, key, errorOut);
   }
@@ -195,7 +195,7 @@ RCT_EXPORT_MODULE()
   NSString *filePath = [self _filePathForKey:key];
   NSError *error;
   if (value.length <= kInlineValueThreshold) {
-    if (_manifest[key] && _manifest[key] != [NSNull null]) {
+    if (_manifest[key] && _manifest[key] != (id)kCFNull) {
       // If the value already existed but wasn't inlined, remove the old file.
       [[NSFileManager defaultManager] removeItemAtPath:filePath error:nil];
     }
@@ -206,7 +206,7 @@ RCT_EXPORT_MODULE()
   if (error) {
     errorOut = RCTMakeError(@"Failed to write value.", error, @{@"key": key});
   } else {
-    _manifest[key] = [NSNull null]; // Mark existence of file with null, any other value is inline data.
+    _manifest[key] = (id)kCFNull; // Mark existence of file with null, any other value is inline data.
   }
   return errorOut;
 }
@@ -223,7 +223,7 @@ RCT_EXPORT_METHOD(multiGet:(NSArray *)keys
 
   id errorOut = [self _ensureSetup];
   if (errorOut) {
-    callback(@[@[errorOut], [NSNull null]]);
+    callback(@[@[errorOut], (id)kCFNull]);
     return;
   }
   NSMutableArray *errors;
@@ -232,7 +232,7 @@ RCT_EXPORT_METHOD(multiGet:(NSArray *)keys
     id keyError = [self _appendItemForKey:key toArray:result];
     RCTAppendError(keyError, &errors);
   }
-  callback(@[errors ?: [NSNull null], result]);
+  callback(@[RCTNullIfNil(errors), result]);
 }
 
 RCT_EXPORT_METHOD(multiSet:(NSArray *)kvPairs
@@ -250,7 +250,7 @@ RCT_EXPORT_METHOD(multiSet:(NSArray *)kvPairs
   }
   [self _writeManifest:&errors];
   if (callback) {
-    callback(@[errors ?: [NSNull null]]);
+    callback(@[RCTNullIfNil(errors)]);
   }
 }
 
@@ -282,7 +282,7 @@ RCT_EXPORT_METHOD(multiMerge:(NSArray *)kvPairs
   }
   [self _writeManifest:&errors];
   if (callback) {
-    callback(@[errors ?: [NSNull null]]);
+    callback(@[RCTNullIfNil(errors)]);
   }
 }
 
@@ -306,7 +306,7 @@ RCT_EXPORT_METHOD(multiRemove:(NSArray *)keys
   }
   [self _writeManifest:&errors];
   if (callback) {
-    callback(@[errors ?: [NSNull null]]);
+    callback(@[RCTNullIfNil(errors)]);
   }
 }
 
@@ -323,7 +323,7 @@ RCT_EXPORT_METHOD(clear:(RCTResponseSenderBlock)callback)
     errorOut = [self _writeManifest:nil];
   }
   if (callback) {
-    callback(@[errorOut ?: [NSNull null]]);
+    callback(@[RCTNullIfNil(errorOut)]);
   }
 }
 
@@ -331,9 +331,9 @@ RCT_EXPORT_METHOD(getAllKeys:(RCTResponseSenderBlock)callback)
 {
   id errorOut = [self _ensureSetup];
   if (errorOut) {
-    callback(@[errorOut, [NSNull null]]);
+    callback(@[errorOut, (id)kCFNull]);
   } else {
-    callback(@[[NSNull null], [_manifest allKeys]]);
+    callback(@[(id)kCFNull, [_manifest allKeys]]);
   }
 }
 

React/Modules/RCTUIManager.m

@@ -471,7 +471,7 @@ static NSDictionary *RCTViewConfigForModule(Class managerClass, NSString *viewNa
     [frames addObject:[NSValue valueWithCGRect:shadowView.frame]];
     [areNew addObject:@(shadowView.isNewView)];
     [parentsAreNew addObject:@(shadowView.superview.isNewView)];
-    id event = [NSNull null];
+    id event = (id)kCFNull;
     if (shadowView.hasOnLayout) {
       event = @{
         @"target": shadowView.reactTag,
@@ -519,7 +519,7 @@ static NSDictionary *RCTViewConfigForModule(Class managerClass, NSString *viewNa
 
       void (^completion)(BOOL finished) = ^(BOOL finished) {
         completionsCalled++;
-        if (event != [NSNull null]) {
+        if (event != (id)kCFNull) {
           [self.bridge.eventDispatcher sendInputEventWithName:@"topLayout" body:event];
         }
         if (callback && completionsCalled == frames.count - 1) {
@@ -753,7 +753,7 @@ static BOOL RCTCallPropertySetter(NSString *key, SEL setter, id value, id view,
   // TODO: cache respondsToSelector tests
   if ([manager respondsToSelector:setter]) {
 
-    if (value == [NSNull null]) {
+    if (value == (id)kCFNull) {
       value = nil;
     }
 
@@ -906,7 +906,7 @@ RCT_EXPORT_METHOD(blur:(NSNumber *)reactTag)
 
 RCT_EXPORT_METHOD(findSubviewIn:(NSNumber *)reactTag atPoint:(CGPoint)point callback:(RCTResponseSenderBlock)callback) {
   if (!reactTag) {
-    callback(@[[NSNull null]]);
+    callback(@[(id)kCFNull]);
     return;
   }
 
@@ -920,7 +920,7 @@ RCT_EXPORT_METHOD(findSubviewIn:(NSNumber *)reactTag atPoint:(CGPoint)point call
     }
 
     callback(@[
-      target.reactTag ?: [NSNull null],
+      RCTNullIfNil(target.reactTag),
       @(frame.origin.x),
       @(frame.origin.y),
       @(frame.size.width),