Refactor handling of keyDown/keyUp (facebook#1338)

This refactors / simplifies certain keyUp|Down event handling.
It will make a later change (adding textInput handling for textInput fields) easier (to review)

Co-authored-by: Scott Kyle <skyle@fb.com>

React/Views/RCTView.h

@@ -25,6 +25,10 @@ extern const UIAccessibilityTraits SwitchAccessibilityTrait;
 
 - (BOOL)becomeFirstResponder;
 - (BOOL)resignFirstResponder;
+
+#if TARGET_OS_OSX
+- (BOOL)handleKeyboardEvent:(NSEvent *)event;
+#endif
 // ]TODO(OSS Candidate ISS#2710739)
 
 /**

React/Views/RCTView.m

@@ -1573,177 +1573,38 @@ - (BOOL)performDragOperation:(id <NSDraggingInfo>)sender
 #pragma mark - Keyboard Events
 
 #if TARGET_OS_OSX
-NSString* const leftArrowPressKey = @"ArrowLeft";
-NSString* const rightArrowPressKey = @"ArrowRight";
-NSString* const upArrowPressKey = @"ArrowUp";
-NSString* const downArrowPressKey = @"ArrowDown";
-
-- (RCTViewKeyboardEvent*)keyboardEvent:(NSEvent*)event downPress:(BOOL)downPress {
-  // modifiers
-  BOOL capsLockKey = NO;
-  BOOL shiftKey = NO;
-  BOOL controlKey = NO;
-  BOOL optionKey = NO;
-  BOOL commandKey = NO;
-  BOOL numericPadKey = NO;
-  BOOL helpKey = NO;
-  BOOL functionKey = NO;
-  // commonly used key short-cuts
-  BOOL leftArrowKey = NO;
-  BOOL rightArrowKey = NO;
-  BOOL upArrowKey = NO;
-  BOOL downArrowKey = NO;
-  BOOL tabKeyPressed = NO;
-  BOOL escapeKeyPressed = NO;
-  NSString *key = event.charactersIgnoringModifiers;
-  if ([key length] == 0) {
-        return nil;
-  }
-  unichar const code = [key characterAtIndex:0];
-
-  // detect arrow key presses
-  if (code == NSLeftArrowFunctionKey) {
-    leftArrowKey = YES;
-  } else if (code == NSRightArrowFunctionKey) {
-    rightArrowKey = YES;
-  } else if (code == NSUpArrowFunctionKey) {
-    upArrowKey = YES;
-  } else if (code == NSDownArrowFunctionKey) {
-    downArrowKey = YES;
-  }
-
-  // detect special key presses via the key code
-  switch (event.keyCode) {
-    case 48: // Tab
-      tabKeyPressed = YES;
-      break;
-    case 53: // Escape
-      escapeKeyPressed = YES;
-      break;
-    default:
-      break;
+- (RCTViewKeyboardEvent*)keyboardEvent:(NSEvent*)event {
+  BOOL keyDown = event.type == NSEventTypeKeyDown;
+  NSArray<NSString *> *validKeys = keyDown ? self.validKeysDown : self.validKeysUp;
+  NSString *key = [RCTViewKeyboardEvent keyFromEvent:event];
+
+  // Only post events for keys we care about
+  if (![validKeys containsObject:key]) {
+    return nil;
   }
 
-  // detect modifier flags
-  if (event.modifierFlags & NSEventModifierFlagCapsLock) {
-    capsLockKey = YES;
-  } else if (event.modifierFlags & NSEventModifierFlagShift) {
-    shiftKey = YES;
-  } else if (event.modifierFlags & NSEventModifierFlagControl) {
-    controlKey = YES;
-  } else if (event.modifierFlags & NSEventModifierFlagOption) {
-    optionKey = YES;
-  } else if (event.modifierFlags & NSEventModifierFlagCommand) {
-    commandKey = YES;
-  } else if (event.modifierFlags & NSEventModifierFlagNumericPad) {
-    numericPadKey = YES;
-  } else if (event.modifierFlags & NSEventModifierFlagHelp) {
-    helpKey = YES;
-  } else if (event.modifierFlags & NSEventModifierFlagFunction) {
-    functionKey = YES;
-  }
-
-  RCTViewKeyboardEvent *keyboardEvent = nil;
-  // only post events for keys we care about
-  if (downPress) {
-    NSString *keyToReturn = [self keyIsValid:key left:leftArrowKey right:rightArrowKey up:upArrowKey down:downArrowKey tabKey:tabKeyPressed escapeKey:escapeKeyPressed validKeys:[self validKeysDown]];
-    if (keyToReturn != nil) {
-      keyboardEvent = [RCTViewKeyboardEvent keyDownEventWithReactTag:self.reactTag
-                                                         capsLockKey:capsLockKey
-                                                            shiftKey:shiftKey
-                                                             ctrlKey:controlKey
-                                                              altKey:optionKey
-                                                             metaKey:commandKey
-                                                       numericPadKey:numericPadKey
-                                                             helpKey:helpKey
-                                                         functionKey:functionKey
-                                                        leftArrowKey:leftArrowKey
-                                                       rightArrowKey:rightArrowKey
-                                                          upArrowKey:upArrowKey
-                                                        downArrowKey:downArrowKey
-                                                                 key:keyToReturn];
-    }
-  } else {
-    NSString *keyToReturn = [self keyIsValid:key left:leftArrowKey right:rightArrowKey up:upArrowKey down:downArrowKey tabKey:tabKeyPressed escapeKey:escapeKeyPressed validKeys:[self validKeysUp]];
-    if (keyToReturn != nil) {
-      keyboardEvent = [RCTViewKeyboardEvent keyUpEventWithReactTag:self.reactTag
-                                                       capsLockKey:capsLockKey
-                                                          shiftKey:shiftKey
-                                                           ctrlKey:controlKey
-                                                            altKey:optionKey
-                                                           metaKey:commandKey
-                                                     numericPadKey:numericPadKey
-                                                           helpKey:helpKey
-                                                       functionKey:functionKey
-                                                      leftArrowKey:leftArrowKey
-                                                     rightArrowKey:rightArrowKey
-                                                        upArrowKey:upArrowKey
-                                                      downArrowKey:downArrowKey
-                                                               key:keyToReturn];
+  return [RCTViewKeyboardEvent keyEventFromEvent:event reactTag:self.reactTag];
+}
+
+- (BOOL)handleKeyboardEvent:(NSEvent *)event {
+  if (event.type == NSEventTypeKeyDown ? self.onKeyDown : self.onKeyUp) {
+    RCTViewKeyboardEvent *keyboardEvent = [self keyboardEvent:event];
+    if (keyboardEvent) {
+      [_eventDispatcher sendEvent:keyboardEvent];
+      return YES;
     }
   }
-  return keyboardEvent;
-}
-
-// check if the user typed key matches a key we need to send an event for
-// translate key codes over to JS compatible keys
-- (NSString*)keyIsValid:(NSString*)key left:(BOOL)leftArrowPressed right:(BOOL)rightArrowPressed up:(BOOL)upArrowPressed down:(BOOL)downArrowPressed tabKey:(BOOL)tabKeyPressed escapeKey:(BOOL)escapeKeyPressed validKeys:(NSArray<NSString*>*)validKeys {
-  NSString *keyToReturn = key;
-
-  // Allow the flexibility of defining special keys in multiple ways
-  BOOL enterKeyValidityCheck = [key isEqualToString:@"\r"] && ([validKeys containsObject:@"Enter"] || [validKeys containsObject:@"\r"]);
-  BOOL tabKeyValidityCheck = tabKeyPressed && ([validKeys containsObject:@"Tab"]); // tab has to be checked via a key code so we can't just use the key itself here
-  BOOL escapeKeyValidityCheck = escapeKeyPressed && ([validKeys containsObject:@"Esc"] || [validKeys containsObject:@"Escape"]); // escape has to be checked via a key code so we can't just use the key itself here
-  BOOL leftArrowValidityCheck = [validKeys containsObject:leftArrowPressKey] && leftArrowPressed;
-  BOOL rightArrowValidityCheck = [validKeys containsObject:rightArrowPressKey] && rightArrowPressed;
-  BOOL upArrowValidityCheck = [validKeys containsObject:upArrowPressKey] && upArrowPressed;
-  BOOL downArrowValidityCheck = [validKeys containsObject:downArrowPressKey] && downArrowPressed;
-
-if (tabKeyValidityCheck) {
-    keyToReturn = @"Tab";
-  } else if (escapeKeyValidityCheck) {
-    keyToReturn = @"Escape";
-  } else if (enterKeyValidityCheck) {
-    keyToReturn = @"Enter";
-  } else if (leftArrowValidityCheck) {
-    keyToReturn = leftArrowPressKey;
-  } else if (rightArrowValidityCheck) {
-    keyToReturn = rightArrowPressKey;
-  } else if (upArrowValidityCheck) {
-    keyToReturn = upArrowPressKey;
-  } else if (downArrowValidityCheck) {
-    keyToReturn = downArrowPressKey;
-  } else if (![validKeys containsObject:key]) {
-    keyToReturn = nil;
-  }
-
-  return keyToReturn;
+  return NO;
 }
 
 - (void)keyDown:(NSEvent *)event {
-  if (self.onKeyDown == nil) {
-    [super keyDown:event];
-    return;
-  }
-
-  RCTViewKeyboardEvent *keyboardEvent = [self keyboardEvent:event downPress:YES];
-  if (keyboardEvent != nil) {
-    [_eventDispatcher sendEvent:keyboardEvent];
-  } else {
+  if (![self handleKeyboardEvent:event]) {
     [super keyDown:event];
   }
 }
 
 - (void)keyUp:(NSEvent *)event {
-  if (self.onKeyUp == nil) {
-    [super keyUp:event];
-    return;
-  }
-
-  RCTViewKeyboardEvent *keyboardEvent = [self keyboardEvent:event downPress:NO];
-  if (keyboardEvent != nil) {
-    [_eventDispatcher sendEvent:keyboardEvent];
-  } else {
+  if (![self handleKeyboardEvent:event]) {
     [super keyUp:event];
   }
 }

React/Views/RCTViewKeyboardEvent.h

@@ -7,33 +7,11 @@
 #import <React/RCTComponentEvent.h>
 
 @interface RCTViewKeyboardEvent : RCTComponentEvent
-+ (instancetype)keyDownEventWithReactTag:(NSNumber *)reactTag
-                             capsLockKey:(BOOL)capsLockKey
-                             shiftKey:(BOOL)shiftKey
-                              ctrlKey:(BOOL)controlKey
-                               altKey:(BOOL)optionKey
-                              metaKey:(BOOL)commandKey
-                        numericPadKey:(BOOL)numericPadKey
-                              helpKey:(BOOL)helpKey
-                          functionKey:(BOOL)functionKey
-                         leftArrowKey:(BOOL)leftArrowKey
-                        rightArrowKey:(BOOL)rightArrowKey
-                           upArrowKey:(BOOL)upArrowKey
-                         downArrowKey:(BOOL)downArrowKey
-                                  key:(NSString *)key;
 
-+ (instancetype)keyUpEventWithReactTag:(NSNumber *)reactTag
-                           capsLockKey:(BOOL)capsLockKey
-                              shiftKey:(BOOL)shiftKey
-                               ctrlKey:(BOOL)controlKey
-                                altKey:(BOOL)optionKey
-                               metaKey:(BOOL)commandKey
-                         numericPadKey:(BOOL)numericPadKey
-                               helpKey:(BOOL)helpKey
-                           functionKey:(BOOL)functionKey
-                          leftArrowKey:(BOOL)leftArrowKey
-                         rightArrowKey:(BOOL)rightArrowKey
-                            upArrowKey:(BOOL)upArrowKey
-                          downArrowKey:(BOOL)downArrowKey
-                                   key:(NSString *)key;
+#if TARGET_OS_OSX // TODO(macOS GH#774)
++ (NSDictionary *)bodyFromEvent:(NSEvent *)event;
++ (NSString *)keyFromEvent:(NSEvent *)event;
++ (instancetype)keyEventFromEvent:(NSEvent *)event reactTag:(NSNumber *)reactTag;
+#endif // TODO(macOS GH#774)
+
 @end

React/Views/RCTViewKeyboardEvent.m

@@ -9,69 +9,66 @@
 #import <React/RCTAssert.h>
 
 @implementation RCTViewKeyboardEvent
-// Keyboard mappings are aligned cross-platform as much as possible as per this doc https://github.com/microsoft/react-native-windows/blob/master/vnext/proposals/active/keyboard-reconcile-desktop.md
-+ (instancetype)keyDownEventWithReactTag:(NSNumber *)reactTag
-                             capsLockKey:(BOOL)capsLockKey
-                                shiftKey:(BOOL)shiftKey
-                                 ctrlKey:(BOOL)controlKey
-                                  altKey:(BOOL)optionKey
-                                 metaKey:(BOOL)commandKey
-                           numericPadKey:(BOOL)numericPadKey
-                                 helpKey:(BOOL)helpKey
-                             functionKey:(BOOL)functionKey
-                            leftArrowKey:(BOOL)leftArrowKey
-                           rightArrowKey:(BOOL)rightArrowKey
-                              upArrowKey:(BOOL)upArrowKey
-                            downArrowKey:(BOOL)downArrowKey
-                                     key:(NSString *)key {
-  RCTViewKeyboardEvent *event = [[self alloc] initWithName:@"keyDown"
-                                                  viewTag:reactTag
-                                                     body:@{ @"capsLockKey" : @(capsLockKey),
-                                                                @"shiftKey" : @(shiftKey),
-                                                                 @"ctrlKey" : @(controlKey),
-                                                                  @"altKey" : @(optionKey),
-                                                                 @"metaKey" : @(commandKey),
-                                                           @"numericPadKey" : @(numericPadKey),
-                                                                 @"helpKey" : @(helpKey),
-                                                             @"functionKey" : @(functionKey),
-                                                               @"ArrowLeft" : @(leftArrowKey),
-                                                              @"ArrowRight" : @(rightArrowKey),
-                                                                 @"ArrowUp" : @(upArrowKey),
-                                                               @"ArrowDown" : @(downArrowKey),
-                                                                     @"key" : key }];
-  return event;
+
+#if TARGET_OS_OSX // TODO(macOS GH#774)
++ (NSDictionary *)bodyFromEvent:(NSEvent *)event
+{
+  NSString *key = [self keyFromEvent:event];
+  NSEventModifierFlags modifierFlags = event.modifierFlags;
+
+  return @{
+    @"key" : key,
+    @"capsLockKey" : (modifierFlags & NSEventModifierFlagCapsLock) ? @YES : @NO,
+    @"shiftKey" : (modifierFlags & NSEventModifierFlagShift) ? @YES : @NO,
+    @"ctrlKey" : (modifierFlags & NSEventModifierFlagControl) ? @YES : @NO,
+    @"altKey" : (modifierFlags & NSEventModifierFlagOption) ? @YES : @NO,
+    @"metaKey" : (modifierFlags & NSEventModifierFlagCommand) ? @YES : @NO,
+    @"numericPadKey" : (modifierFlags & NSEventModifierFlagNumericPad) ? @YES : @NO,
+    @"helpKey" : (modifierFlags & NSEventModifierFlagHelp) ? @YES : @NO,
+    @"functionKey" : (modifierFlags & NSEventModifierFlagFunction) ? @YES : @NO,
+  };
 }
 
-+(instancetype)keyUpEventWithReactTag:(NSNumber *)reactTag
-                          capsLockKey:(BOOL)capsLockKey
-                             shiftKey:(BOOL)shiftKey
-                              ctrlKey:(BOOL)controlKey
-                               altKey:(BOOL)optionKey
-                              metaKey:(BOOL)commandKey
-                        numericPadKey:(BOOL)numericPadKey
-                              helpKey:(BOOL)helpKey
-                          functionKey:(BOOL)functionKey
-                         leftArrowKey:(BOOL)leftArrowKey
-                        rightArrowKey:(BOOL)rightArrowKey
-                           upArrowKey:(BOOL)upArrowKey
-                         downArrowKey:(BOOL)downArrowKey
-                                   key:(NSString *)key {
-  RCTViewKeyboardEvent *event = [[self alloc] initWithName:@"keyUp"
-                                                  viewTag:reactTag
-                                                     body:@{ @"capsLockKey" : @(capsLockKey),
-                                                                @"shiftKey" : @(shiftKey),
-                                                                 @"ctrlKey" : @(controlKey),
-                                                                  @"altKey" : @(optionKey),
-                                                                 @"metaKey" : @(commandKey),
-                                                           @"numericPadKey" : @(numericPadKey),
-                                                                 @"helpKey" : @(helpKey),
-                                                             @"functionKey" : @(functionKey),
-                                                               @"ArrowLeft" : @(leftArrowKey),
-                                                              @"ArrowRight" : @(rightArrowKey),
-                                                                 @"ArrowUp" : @(upArrowKey),
-                                                               @"ArrowDown" : @(downArrowKey),
-                                                                     @"key" : key }];
-  return event;
++ (NSString *)keyFromEvent:(NSEvent *)event
+{
+  NSString *key = event.charactersIgnoringModifiers;
+  unichar const code = key.length > 0 ? [key characterAtIndex:0] : 0;
+
+  if (event.keyCode == 48) {
+    return @"Tab";
+  } else if (event.keyCode == 53) {
+    return @"Escape";
+  } else if (code == NSEnterCharacter || code == NSNewlineCharacter || code == NSCarriageReturnCharacter) {
+    return @"Enter";
+  } else if (code == NSLeftArrowFunctionKey) {
+    return @"ArrowLeft";
+  } else if (code == NSRightArrowFunctionKey) {
+    return @"ArrowRight";
+  } else if (code == NSUpArrowFunctionKey) {
+    return @"ArrowUp";
+  } else if (code == NSDownArrowFunctionKey) {
+    return @"ArrowDown";
+  } else if (code == NSBackspaceCharacter || code == NSDeleteCharacter) {
+    return @"Backspace";
+  } else if (code == NSDeleteFunctionKey) {
+    return @"Delete";
+  }
+
+  return key;
+}
+
+// Keyboard mappings are aligned cross-platform as much as possible as per this doc https://github.com/microsoft/react-native-windows/blob/master/vnext/proposals/active/keyboard-reconcile-desktop.md
++ (instancetype)keyEventFromEvent:(NSEvent *)event reactTag:(NSNumber *)reactTag
+{
+  // Ignore "dead keys" (key press that waits for another key to make a character)
+  if (!event.charactersIgnoringModifiers.length) {
+    return nil;
+  }
+
+  return [[self alloc] initWithName:(event.type == NSEventTypeKeyDown ? @"keyDown" : @"keyUp")
+                            viewTag:reactTag
+                               body:[self bodyFromEvent:event]];
 }
+#endif // TODO(macOS GH#774)
 
 @end

packages/rn-tester/js/examples/KeyboardEventsExample/KeyboardEventsExample.js

@@ -53,7 +53,7 @@ class KeyEventExample extends React.Component<{}, State> {
           {Platform.OS === 'macos' ? (
             <View
               focusable={true}
-              validKeysDown={['g', 'Tab', 'Esc', 'Enter', 'ArrowLeft']}
+              validKeysDown={['g', 'Tab', 'Escape', 'Enter', 'ArrowLeft']}
               onKeyDown={this.onKeyDownEvent}
               validKeysUp={['c', 'd']}
               onKeyUp={this.onKeyUpEvent}>