[Key handling] pass through all keys; allow specifying modifiers for validKeys[Down|Up] (#1867)

* [Key handling] pass through all keys; allow specifying modifiers for validKeys[Down|Up]

There are scenarios where it might be necessary to look at the incoming events without removing from the system queue. Currently that's impossible today on React Native macOS, since views are required to specify `validKeysDown` or `validKeysUp`, and such events are always removed from the queue.

To mitigate, let's add a new `passthroughAllKeyEvents` prop to `RCTView`. We could keep it forever (towards an interest to reduce event spam from native to JS), or we could use it towards the path to making it the default behavior (stage 1: default false, i.e. opt in, stage 2: default true, i.e. opt out, stage 3: remove, is default behavior).
- React/Views/RCTView.h
- React/Views/RCTView.m
- React/Views/RCTViewManager.m

Note that this doesn't properly work with `RCTUITextField` (i.e. single line text fields). From what I can tell, that would need us to possibly provide a custom field editor for the window. I am scoping this out for this PR.

Another peculiarity to note is regarding `RCTUITextView` (i.e. multi line text fields). Here, it looks like the text view itself isn't exposed to the JS (this view doesn't have a `nativeTag`), so there's a `RCTView` holding a child `RCTUITextView` where the former dispatches events to JS on behalf for the latter. The reason this matters (specifically for "pass through" events) is because the latter can dispatch certain events to the JS, and then depending on the super class implementation (`NSTextView`), it may or may not *also* pass the `NSEvent` to the next responder (i.e. parent view, i.e. `RCTView`). Passing the action to the next responder *can* cause us to send duplicate JS events for the same `NSEvent`. I couldn't find anything in macOS APIs to determine if the view the event was generated for is a specific view, so I am introducing a book-keeping mechanism to not send duplicate events.

Introduce `RCTHandledKey` for specifying modifiers for `validKeysDown` and `validKeysUp`. Behavior noted in type definitions.
- Libraries/Text/TextInput/RCTBaseTextInputView.m
- React/Base/RCTConvert.h
- React/Base/RCTConvert.m
- React/Views/RCTHandledKey.h
- React/Views/RCTHandledKey.m
- React/Views/RCTView.h
- React/Views/RCTView.m
- React/Views/RCTViewKeyboardEvent.m
- React/Views/RCTViewManager.m
- React/Views/ScrollView/RCTScrollView.m

macOS *usually* does things on key down (as opposed to, say, Win32, which seems to *usually* does things on key up). Like `RCTUITextField`, passs `performKeyEquivalent:` to `textInputDelegate` so we can handle the alternate `keyDown:` path (e.g. Cmd+A). This will be needed for properly handling keystrokes that go through said alternate path. There are probably several other selectors that also need implementing (`deleteBackward:`) to full pass through every possible key, but I am leaving that for some other time.
- Libraries/Text/TextInput/Multiline/RCTUITextView.m

Make a totally unrelated fix to `RCTSwitch`. In a test page where I added an on-by-default switch, I noticed the first toggle (ON->OFF) doesn't do anything. The second toggle (OFF->ON) then doesn't (expectedly) do anything. Found wrong behavior on the switch test page -- tempted to instead remove `wasOn`, but for now repeating the pattern in `setOn:animated:`
- React/Views/RCTSwitch.m

Flow stuff. `passthroughAllKeyEvents` is now a valid thing to pass to `View` types.
- Libraries/Components/View/ReactNativeViewAttributes.js
- Libraries/Components/View/ViewPropTypes.js
- Libraries/NativeComponent/BaseViewConfig.macos.js

Update signatures for `validKeysDown` and `validKeysUp`
- Libraries/Components/View/ViewPropTypes.js

Remove duplicated specifications on `Pressable`. Just use the one from `View`. As a benefit, future changes allow us to not have to touch `Pressable` anymore.
- Libraries/Components/Pressable/Pressable.js
- Libraries/Components/View/ViewPropTypes.js

Update test pages with `passthoughAllKeyEvents` and the keyboard events page with an example modifier usage.
- packages/rn-tester/js/examples/KeyboardEventsExample/KeyboardEventsExample.js
- packages/rn-tester/js/examples/TextInput/TextInputSharedExamples.js

Testing:

* Using the keyboard events test page, validate "pass through" of all events for simple view, single line text input, multi line text input. Sanity test existing (non-"pass through") behavior.
* Using the text input test page, ordering of `keyDown` and `keyUp` events w.r.t. other events (such as `keyPress` -- which isn't dispatched for every key)
* Using the switch test page, sanity test switch behaviors

* feedback

* feedback #2

* PR feedback

---------

Co-authored-by: Saad Najmi <saadnajmi2@gmail.com>

Author: nakambo

Libraries/Components/Pressable/Pressable.js

@@ -26,6 +26,7 @@ import type {
   AccessibilityState,
   AccessibilityValue,
 } from '../View/ViewAccessibility';
+import type {HandledKeyboardEvent} from '../View/ViewPropTypes'; // [macOS]
 
 import {PressabilityDebugView} from '../../Pressability/PressabilityDebug';
 import usePressability from '../../Pressability/usePressability';
@@ -185,16 +186,27 @@ type Props = $ReadOnly<{|
   onKeyUp?: ?(event: KeyEvent) => void,
 
   /**
-   * Array of keys to receive key down events for
-   * For arrow keys, add "ArrowLeft", "ArrowRight", "ArrowUp", "ArrowDown",
+   * When `true`, allows `onKeyDown` and `onKeyUp` to receive events not specified in
+   * `validKeysDown` and `validKeysUp`, respectively. Events matching `validKeysDown` and `validKeysUp`
+   * still have their native default behavior prevented, but the others do not.
+   *
+   * @platform macos
    */
-  validKeysDown?: ?Array<string>,
+  passthroughAllKeyEvents?: ?boolean,
 
   /**
-   * Array of keys to receive key up events for
-   * For arrow keys, add "ArrowLeft", "ArrowRight", "ArrowUp", "ArrowDown",
+   * Array of keys to receive key down events for. These events have their default native behavior prevented.
+   *
+   * @platform macos
+   */
+  validKeysDown?: ?Array<string | HandledKeyboardEvent>,
+
+  /**
+   * Array of keys to receive key up events for. These events have their default native behavior prevented.
+   *
+   * @platform macos
    */
-  validKeysUp?: ?Array<string>,
+  validKeysUp?: ?Array<string | HandledKeyboardEvent>,
 
   /**
    * Specifies whether the view should receive the mouse down event when the

Libraries/Components/View/ReactNativeViewAttributes.js

@@ -47,6 +47,7 @@ const UIView = {
   onDrop: true,
   onKeyDown: true,
   onKeyUp: true,
+  passthroughAllKeyEvents: true,
   validKeysDown: true,
   validKeysUp: true,
   draggedTypes: true,

Libraries/Components/View/ViewPropTypes.js

@@ -100,22 +100,58 @@ type DirectEventProps = $ReadOnly<{|
 |}>;
 
 // [macOS
-type KeyboardEventProps = $ReadOnly<{|
+/**
+ * Represents a key that could be passed to `validKeysDown` and `validKeysUp`.
+ *
+ * `key` is the actual key, such as "a", or one of the special values:
+ * "Tab", "Escape", "Enter", "ArrowLeft", "ArrowRight", "ArrowUp", "ArrowDown",
+ * "Backspace", "Delete", "Home", "End", "PageUp", "PageDown".
+ *
+ * The rest are modifiers that when absent mean false.
+ *
+ * @platform macos
+ */
+export type HandledKeyboardEvent = $ReadOnly<{|
+  altKey?: ?boolean,
+  ctrlKey?: ?boolean,
+  metaKey?: ?boolean,
+  shiftKey?: ?boolean,
+  key: string,
+|}>;
+
+export type KeyboardEventProps = $ReadOnly<{|
+  /**
+   * Called after a key down event is detected.
+   */
   onKeyDown?: ?(event: KeyEvent) => void,
+
+  /**
+   * Called after a key up event is detected.
+   */
   onKeyUp?: ?(event: KeyEvent) => void,
+
+  /**
+   * When `true`, allows `onKeyDown` and `onKeyUp` to receive events not specified in
+   * `validKeysDown` and `validKeysUp`, respectively. Events matching `validKeysDown` and `validKeysUp`
+   * are still removed from the event queue, but the others are not.
+   *
+   * @platform macos
+   */
+  passthroughAllKeyEvents?: ?boolean,
+
   /**
-   * Array of keys to receive key down events for
+   * Array of keys to receive key down events for. These events have their default native behavior prevented.
    *
    * @platform macos
    */
-  validKeysDown?: ?Array<string>,
+  validKeysDown?: ?Array<string | HandledKeyboardEvent>,
 
   /**
-   * Array of keys to receive key up events for
+   * Array of keys to receive key up events for. These events have their default native behavior prevented.
    *
    * @platform macos
    */
-  validKeysUp?: ?Array<string>,
+  validKeysUp?: ?Array<string | HandledKeyboardEvent>,
 |}>;
 // macOS]
 

Libraries/NativeComponent/BaseViewConfig.macos.js

@@ -52,6 +52,7 @@ const validAttributesForNonEventProps = {
   draggedTypes: true,
   enableFocusRing: true,
   tooltip: true,
+  passthroughAllKeyEvents: true,
   validKeysDown: true,
   validKeysUp: true,
   mouseDownCanMoveWindow: true,

Libraries/Text/TextInput/Multiline/RCTUITextView.m

@@ -555,6 +555,14 @@ - (void)deleteBackward {
   }
 }
 #else // [macOS
+- (BOOL)performKeyEquivalent:(NSEvent *)event {
+  if (!self.hasMarkedText && ![self.textInputDelegate textInputShouldHandleKeyEvent:event]) {
+    return YES;
+  }
+
+  return [super performKeyEquivalent:event];
+}
+
 - (void)keyDown:(NSEvent *)event {
   // If has marked text, handle by native and return
   // Do this check before textInputShouldHandleKeyEvent as that one attempts to send the event to JS

Libraries/Text/TextInput/RCTBaseTextInputView.m

@@ -21,6 +21,7 @@
 #import <React/RCTTextSelection.h>
 #import <React/RCTUITextView.h> // [macOS]
 #import "../RCTTextUIKit.h" // [macOS]
+#import <React/RCTHandledKey.h> // [macOS]
 
 @implementation RCTBaseTextInputView {
   __weak RCTBridge *_bridge;
@@ -668,7 +669,8 @@ - (BOOL)textInputShouldHandleDeleteForward:(__unused id)sender {
 }
 
 - (BOOL)hasValidKeyDownOrValidKeyUp:(NSString *)key {
-  return [self.validKeysDown containsObject:key] || [self.validKeysUp containsObject:key];
+  return [RCTHandledKey key:key matchesFilter:self.validKeysDown]
+	||  [RCTHandledKey key:key matchesFilter:self.validKeysUp];
 }
 
 - (NSDragOperation)textInputDraggingEntered:(id<NSDraggingInfo>)draggingInfo

React/Base/RCTConvert.h

@@ -20,6 +20,8 @@
 #import <WebKit/WebKit.h>
 #endif
 
+@class RCTHandledKey; // [macOS]
+
 /**
  * This class provides a collection of conversion functions for mapping
  * JSON objects to native types and classes. These are useful when writing
@@ -147,6 +149,8 @@ typedef BOOL css_backface_visibility_t;
 
 #if TARGET_OS_OSX // [macOS
 + (NSString *)accessibilityRoleFromTraits:(id)json;
+
++ (NSArray<RCTHandledKey *> *)RCTHandledKeyArray:(id)json;
 #endif // macOS]
 @end
 

React/Base/RCTConvert.m

@@ -12,6 +12,7 @@
 #import <CoreText/CoreText.h>
 
 #import "RCTDefines.h"
+#import "RCTHandledKey.h" // [macOS]
 #import "RCTImageSource.h"
 #import "RCTParserUtils.h"
 #import "RCTUtils.h"
@@ -1500,6 +1501,9 @@ + (NSString *)accessibilityRoleFromTraits:(id)json
   }
   return NSAccessibilityUnknownRole;
 }
+
+RCT_JSON_ARRAY_CONVERTER(RCTHandledKey);
+
 #endif // macOS]
 
 @end

React/Views/RCTHandledKey.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// [macOS]
+
+#if TARGET_OS_OSX
+#import <React/RCTConvert.h>
+
+// This class is used for specifying key filtering e.g. for -[RCTView validKeysDown] and -[RCTView validKeysUp]
+// Also see RCTViewKeyboardEvent, which is a React representation of an actual NSEvent that is dispatched to JS.
+@interface RCTHandledKey : NSObject
+
++ (BOOL)event:(NSEvent *)event matchesFilter:(NSArray<RCTHandledKey *> *)filter;
++ (BOOL)key:(NSString *)key matchesFilter:(NSArray<RCTHandledKey *> *)filter;
+
+- (instancetype)initWithKey:(NSString *)key;
+- (BOOL)matchesEvent:(NSEvent *)event;
+
+@property (nonatomic, copy) NSString *key;
+
+// For the following modifiers, nil means we don't care about the presence of the modifier when filtering the key
+// They are still expected to be only boolean when not nil.
+@property (nonatomic, assign) NSNumber *altKey;
+@property (nonatomic, assign) NSNumber *ctrlKey;
+@property (nonatomic, assign) NSNumber *metaKey;
+@property (nonatomic, assign) NSNumber *shiftKey;
+
+@end
+
+@interface RCTConvert (RCTHandledKey)
+
++ (RCTHandledKey *)RCTHandledKey:(id)json;
+
+@end
+
+#endif

React/Views/RCTHandledKey.m

@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// [macOS]
+
+#import "objc/runtime.h"
+#import <React/RCTAssert.h>
+#import <React/RCTUtils.h>
+#import <RCTConvert.h>
+#import <RCTHandledKey.h>
+#import <RCTViewKeyboardEvent.h>
+
+#if TARGET_OS_OSX
+
+@implementation RCTHandledKey
+
++ (NSArray<NSString *> *)validModifiers {
+  // keep in sync with actual properties and RCTViewKeyboardEvent
+  return @[@"altKey", @"ctrlKey", @"metaKey", @"shiftKey"];
+}
+
++ (BOOL)event:(NSEvent *)event matchesFilter:(NSArray<RCTHandledKey *> *)filter {
+  for (RCTHandledKey *key in filter) {
+	if ([key matchesEvent:event]) {
+	  return YES;
+	}
+  }
+
+  return NO;
+}
+
++ (BOOL)key:(NSString *)key matchesFilter:(NSArray<RCTHandledKey *> *)filter {
+  for (RCTHandledKey *aKey in filter) {
+	if ([[aKey key] isEqualToString:key]) {
+	  return YES;
+	}
+  }
+
+  return NO;
+}
+
+- (instancetype)initWithKey:(NSString *)key {
+  if ((self = [super init])) {
+    self.key = key;
+  }
+  return self;
+}
+
+- (BOOL)matchesEvent:(NSEvent *)event
+{
+  NSEventType type = [event type];
+  if (type != NSEventTypeKeyDown && type != NSEventTypeKeyUp) {
+    RCTFatal(RCTErrorWithMessage([NSString stringWithFormat:@"Wrong event type (%d) sent to -[RCTHandledKey matchesEvent:]", (int)type]));
+    return NO;
+  }
+
+  NSDictionary *body = [RCTViewKeyboardEvent bodyFromEvent:event];
+  NSString *key = body[@"key"];
+  if (key == nil) {
+    RCTFatal(RCTErrorWithMessage(@"Event body has missing value for 'key'"));
+    return NO;
+  }
+
+  if (![key isEqualToString:self.key]) {
+    return NO;
+  }
+
+  NSArray<NSString *> *modifiers = [RCTHandledKey validModifiers];
+  for (NSString *modifier in modifiers) {
+    NSNumber *myValue = [self valueForKey:modifier];
+
+    if (myValue == nil) {
+		continue;
+	}
+
+	NSNumber *eventValue = (NSNumber *)body[modifier];
+	if (eventValue == nil) {
+		RCTFatal(RCTErrorWithMessage([NSString stringWithFormat:@"Event body has missing value for '%@'", modifier]));
+		return NO;
+	}
+
+	if (![eventValue isKindOfClass:[NSNumber class]]) {
+		RCTFatal(RCTErrorWithMessage([NSString stringWithFormat:@"Event body has unexpected value of class '%@' for '%@'",
+			NSStringFromClass(object_getClass(eventValue)), modifier]));
+		return NO;
+    }
+
+	if (![myValue isEqualToNumber:body[modifier]]) {
+		return NO;
+	}
+  }
+
+  return YES;  // keys matched; all present modifiers matched
+}
+
+@end
+
+@implementation RCTConvert (RCTHandledKey)
+
++ (RCTHandledKey *)RCTHandledKey:(id)json
+{
+  // legacy way of specifying validKeysDown and validKeysUp -- here we ignore the modifiers when comparing to the NSEvent
+  if ([json isKindOfClass:[NSString class]]) {
+    return [[RCTHandledKey alloc] initWithKey:(NSString *)json];
+  }
+
+  // modern way of specifying validKeys and validKeysUp -- here we assume missing modifiers to mean false\NO
+  if ([json isKindOfClass:[NSDictionary class]]) {
+    NSDictionary *dict = (NSDictionary *)json;
+    NSString *key = dict[@"key"];
+    if (key == nil) {
+      RCTLogConvertError(dict, @"a RCTHandledKey -- must include \"key\"");
+      return nil;
+    }
+
+	RCTHandledKey *handledKey = [[RCTHandledKey alloc] initWithKey:key];
+    NSArray<NSString *> *modifiers = RCTHandledKey.validModifiers;
+    for (NSString *key in modifiers) {
+      id value = dict[key];
+      if (value == nil) {
+        value = @NO;	// assume NO -- instead of nil i.e. "don't care" unlike the string case above.
+	  }
+
+      if (![value isKindOfClass:[NSNumber class]]) {
+        RCTLogConvertError(value, @"a boolean");
+        return nil;
+      }
+
+      [handledKey setValue:@([(NSNumber *)value boolValue]) forKey:key];
+    }
+
+    return handledKey;
+  }
+
+  RCTLogConvertError(json, @"a RCTHandledKey -- allowed types are string and object");
+  return nil;
+}
+
+@end
+
+#endif