From b0982971c6ed6be98b99db902a38dfdf5e9b8b37 Mon Sep 17 00:00:00 2001
From: Riccardo Cipolleschi <cipolleschi@meta.com>
Date: Thu, 14 Dec 2023 08:52:54 -0800
Subject: [PATCH] Improve setting props of the Interop Layer (#41942)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/41942

Previously, every time a component was updated, we were passing all the props to the interoperated component.
With this change, we are going to only pass the props that are changed.

As a safety feature, if the new codepath is not able to detect the type of the prop properly, it will fall back to the previous behavior.

## Changelog:
[Internal] - Only pass props to the interoperated component when they changes

Reviewed By: sammy-SC

Differential Revision: D51755764

fbshipit-source-id: 0185d2cceeab2a1e45b87d5a1e82ab06e00aa82d
---
 .../RCTLegacyViewManagerInteropCoordinator.mm | 89 ++++++++++++++++++-
 1 file changed, 87 insertions(+), 2 deletions(-)

diff --git a/packages/react-native/ReactCommon/react/renderer/components/legacyviewmanagerinterop/RCTLegacyViewManagerInteropCoordinator.mm b/packages/react-native/ReactCommon/react/renderer/components/legacyviewmanagerinterop/RCTLegacyViewManagerInteropCoordinator.mm
index afaea7424dd5f6..5424099638f374 100644
--- a/packages/react-native/ReactCommon/react/renderer/components/legacyviewmanagerinterop/RCTLegacyViewManagerInteropCoordinator.mm
+++ b/packages/react-native/ReactCommon/react/renderer/components/legacyviewmanagerinterop/RCTLegacyViewManagerInteropCoordinator.mm
@@ -41,6 +41,8 @@ @implementation RCTLegacyViewManagerInteropCoordinator {
    */
   NSMutableArray<id<RCTBridgeMethod>> *_moduleMethods;
   NSMutableDictionary<NSString *, id<RCTBridgeMethod>> *_moduleMethodsByName;
+
+  NSDictionary<NSString *, id> *_oldProps;
 }
 
 - (instancetype)initWithComponentData:(RCTComponentData *)componentData
@@ -100,11 +102,13 @@ - (void)setProps:(const folly::dynamic &)props forView:(UIView *)view
 {
   if (props.isObject()) {
     NSDictionary<NSString *, id> *convertedProps = convertFollyDynamicToId(props);
-    [_componentData setProps:convertedProps forView:view];
+    NSDictionary<NSString *, id> *diffedProps = [self _diffProps:convertedProps];
+    [_componentData setProps:diffedProps forView:view];
 
     if ([view respondsToSelector:@selector(didSetProps:)]) {
-      [view performSelector:@selector(didSetProps:) withObject:[convertedProps allKeys]];
+      [view performSelector:@selector(didSetProps:) withObject:[diffedProps allKeys]];
     }
+    _oldProps = convertedProps;
   }
 }
 
@@ -248,4 +252,85 @@ - (void)_lookupModuleMethodsIfNecessary
   }
 }
 
+- (NSDictionary<NSString *, id> *)_diffProps:(NSDictionary<NSString *, id> *)newProps
+{
+  NSMutableDictionary<NSString *, id> *diffedProps = [NSMutableDictionary new];
+
+  [newProps enumerateKeysAndObjectsUsingBlock:^(NSString *key, id newProp, __unused BOOL *stop) {
+    id oldProp = _oldProps[key];
+    if ([self _prop:newProp isDifferentFrom:oldProp]) {
+      diffedProps[key] = newProp;
+    }
+  }];
+
+  return diffedProps;
+}
+
+- (BOOL)_prop:(id)oldProp isDifferentFrom:(id)newProp
+{
+  // Check for JSON types.
+  // JSON types can be of:
+  // * number
+  // * bool
+  // * String
+  // * Array
+  // * Objects => Dictionaries in ObjectiveC
+  // * Null
+
+  // Check for NULL
+  BOOL bothNil = !oldProp && !newProp;
+  if (bothNil) {
+    return NO;
+  }
+
+  BOOL onlyOneNil = (oldProp && !newProp) || (!oldProp && newProp);
+  if (onlyOneNil) {
+    return YES;
+  }
+
+  if ([self _propIsSameNumber:oldProp second:newProp]) {
+    // Boolean should be captured by NSNumber
+    return NO;
+  }
+
+  if ([self _propIsSameString:oldProp second:newProp]) {
+    return NO;
+  }
+
+  if ([self _propIsSameArray:oldProp second:newProp]) {
+    return NO;
+  }
+
+  if ([self _propIsSameObject:oldProp second:newProp]) {
+    return NO;
+  }
+
+  // Previous behavior, fallback to YES
+  return YES;
+}
+
+- (BOOL)_propIsSameNumber:(id)first second:(id)second
+{
+  return [first isKindOfClass:[NSNumber class]] && [second isKindOfClass:[NSNumber class]] &&
+      [(NSNumber *)first isEqualToNumber:(NSNumber *)second];
+}
+
+- (BOOL)_propIsSameString:(id)first second:(id)second
+{
+  return [first isKindOfClass:[NSString class]] && [second isKindOfClass:[NSString class]] &&
+      [(NSString *)first isEqualToString:(NSString *)second];
+}
+
+- (BOOL)_propIsSameArray:(id)first second:(id)second
+{
+  return [first isKindOfClass:[NSArray class]] && [second isKindOfClass:[NSArray class]] &&
+      [(NSArray *)first isEqualToArray:(NSArray *)second];
+}
+
+- (BOOL)_propIsSameObject:(id)first second:(id)second
+{
+  return [first isKindOfClass:[NSDictionary class]] && [second isKindOfClass:[NSDictionary class]] &&
+      [(NSDictionary *)first isEqualToDictionary:(NSDictionary *)second];
+}
+
 @end