Make class prop resolution faster (#28766)

`delete` causes an object (in V8, and maybe other engines) to deopt to a
dictionary instead of a class. Instead of `assign` + `delete`, manually
iterate over all the properties, like the JSX runtime does.

To avoid copying the object twice I moved the `ref` prop removal to come
before handling default props. If we already cloned the props to remove
`ref`, then we can skip cloning again to handle default props.

DiffTrain build for [bfd8da8](bfd8da8)

Author: acdlite

compiled/facebook-www/REVISION

@@ -1 +1 @@
-cbb6f2b5461cdce282c7e47b9c68a0897d393383
+bfd8da807c75a2d123627415f9eaf2d36ac3ed6a

compiled/facebook-www/ReactART-dev.classic.js

@@ -66,7 +66,7 @@ if (__DEV__) {
       return self;
     }
 
-    var ReactVersion = "19.0.0-www-classic-da2c086d";
+    var ReactVersion = "19.0.0-www-classic-fcdce517";
 
     var LegacyRoot = 0;
     var ConcurrentRoot = 1;
@@ -14287,7 +14287,20 @@ if (__DEV__) {
       // remove this extra check.
       alreadyResolvedDefaultProps
     ) {
-      var newProps = baseProps; // Resolve default props. Taken from old JSX runtime, where this used to live.
+      var newProps = baseProps;
+
+      if (enableRefAsProp) {
+        // Remove ref from the props object, if it exists.
+        if ("ref" in baseProps) {
+          newProps = {};
+
+          for (var propName in baseProps) {
+            if (propName !== "ref") {
+              newProps[propName] = baseProps[propName];
+            }
+          }
+        }
+      } // Resolve default props.
 
       var defaultProps = Component.defaultProps;
 
@@ -14296,26 +14309,19 @@ if (__DEV__) {
         // default props here in the reconciler, rather than in the JSX runtime.
         (disableDefaultPropsExceptForClasses || !alreadyResolvedDefaultProps)
       ) {
-        newProps = assign({}, newProps, baseProps);
+        // We may have already copied the props object above to remove ref. If so,
+        // we can modify that. Otherwise, copy the props object with Object.assign.
+        if (newProps === baseProps) {
+          newProps = assign({}, newProps, baseProps);
+        } // Taken from old JSX runtime, where this used to live.
 
-        for (var propName in defaultProps) {
-          if (newProps[propName] === undefined) {
-            newProps[propName] = defaultProps[propName];
+        for (var _propName in defaultProps) {
+          if (newProps[_propName] === undefined) {
+            newProps[_propName] = defaultProps[_propName];
           }
         }
       }
 
-      if (enableRefAsProp) {
-        // Remove ref from the props object, if it exists.
-        if ("ref" in newProps) {
-          if (newProps === baseProps) {
-            newProps = assign({}, newProps);
-          }
-
-          delete newProps.ref;
-        }
-      }
-
       return newProps;
     }
 

compiled/facebook-www/ReactART-dev.modern.js

@@ -66,7 +66,7 @@ if (__DEV__) {
       return self;
     }
 
-    var ReactVersion = "19.0.0-www-modern-a4bdb396";
+    var ReactVersion = "19.0.0-www-modern-f3bc72db";
 
     var LegacyRoot = 0;
     var ConcurrentRoot = 1;
@@ -13997,7 +13997,20 @@ if (__DEV__) {
       // remove this extra check.
       alreadyResolvedDefaultProps
     ) {
-      var newProps = baseProps; // Resolve default props. Taken from old JSX runtime, where this used to live.
+      var newProps = baseProps;
+
+      if (enableRefAsProp) {
+        // Remove ref from the props object, if it exists.
+        if ("ref" in baseProps) {
+          newProps = {};
+
+          for (var propName in baseProps) {
+            if (propName !== "ref") {
+              newProps[propName] = baseProps[propName];
+            }
+          }
+        }
+      } // Resolve default props.
 
       var defaultProps = Component.defaultProps;
 
@@ -14006,26 +14019,19 @@ if (__DEV__) {
         // default props here in the reconciler, rather than in the JSX runtime.
         (disableDefaultPropsExceptForClasses || !alreadyResolvedDefaultProps)
       ) {
-        newProps = assign({}, newProps, baseProps);
+        // We may have already copied the props object above to remove ref. If so,
+        // we can modify that. Otherwise, copy the props object with Object.assign.
+        if (newProps === baseProps) {
+          newProps = assign({}, newProps, baseProps);
+        } // Taken from old JSX runtime, where this used to live.
 
-        for (var propName in defaultProps) {
-          if (newProps[propName] === undefined) {
-            newProps[propName] = defaultProps[propName];
+        for (var _propName in defaultProps) {
+          if (newProps[_propName] === undefined) {
+            newProps[_propName] = defaultProps[_propName];
           }
         }
       }
 
-      if (enableRefAsProp) {
-        // Remove ref from the props object, if it exists.
-        if ("ref" in newProps) {
-          if (newProps === baseProps) {
-            newProps = assign({}, newProps);
-          }
-
-          delete newProps.ref;
-        }
-      }
-
       return newProps;
     }