earlyjs: Implement decoratedExtraDataKey (#46932)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/46932

In the old error handling pipeline, when the app [assigns an object to error[ExceptionsManager.decoratedExtraDataKey]](https://fburl.com/code/9t9u8rgv)

```
        const error = new Error('Some error happened');
        // Annotates the error with some custom extra data.
        error[ExceptionsManager.decoratedExtraDataKey] = {foo: 'bar'};
        ExceptionsManager.handleException(error, true);
```

That object [gets forwarded as extraData](https://fburl.com/code/gy7v173u) to ExceptionsManager.

This diff implements that functionality within the c++ earlyjs pipeline.

Changelog: [Internal]

Reviewed By: javache

Differential Revision: D63927091

fbshipit-source-id: ac88bf3e545714aa42531e8e1365e2eba32a7c2b

packages/react-native/Libraries/Core/ExceptionsManager.js

@@ -22,10 +22,11 @@ type ExceptionDecorator = ExceptionData => ExceptionData;
 let userExceptionDecorator: ?ExceptionDecorator;
 let inUserExceptionDecorator = false;
 
-// This Symbol is used to decorate an ExtendedError with extra data in select usecases.
+// This string is used to decorate an ExtendedError with extra data in select usecases.
 // Note that data passed using this method should be strictly contained,
 // as data that's not serializable/too large may cause issues with passing the error to the native code.
-const decoratedExtraDataKey: symbol = Symbol('decoratedExtraDataKey');
+// TODO(T204185517): We should use a Symbol for this, but jsi through jsc doesn't support it yet.
+const decoratedExtraDataKey = 'RN$ErrorExtraDataKey';
 
 /**
  * Allows the app to add information to the exception report before it is sent

packages/react-native/Libraries/__tests__/__snapshots__/public-api-test.js.snap

@@ -4338,7 +4338,7 @@ exports[`public API should not change unintentionally Libraries/Core/ExceptionsM
   name: string;
 }
 type ExceptionDecorator = (ExceptionData) => ExceptionData;
-declare const decoratedExtraDataKey: symbol;
+declare const decoratedExtraDataKey: \\"RN$ErrorExtraDataKey\\";
 declare function unstable_setExceptionDecorator(
   exceptionDecorator: ?ExceptionDecorator
 ): void;

packages/react-native/ReactCommon/jsc/JSCRuntime.cpp

@@ -668,9 +668,9 @@ jsi::PropNameID JSCRuntime::createPropNameIDFromString(const jsi::String& str) {
 }
 
 jsi::PropNameID JSCRuntime::createPropNameIDFromSymbol(const jsi::Symbol& sym) {
-  // TODO: Support for symbols through the native API in JSC is very limited.
-  // While we could construct a PropNameID here, we would not be able to get a
-  // symbol property through the C++ API.
+  // TODO(T204185517): Support for symbols through the native API in JSC is very
+  // limited. While we could construct a PropNameID here, we would not be able
+  // to get a symbol property through the C++ API.
   throw std::logic_error("Not implemented");
 }
 

packages/react-native/ReactCommon/jserrorhandler/JsErrorHandler.cpp

@@ -41,6 +41,15 @@ bool isTruthy(jsi::Runtime& runtime, const jsi::Value& value) {
   auto Boolean = runtime.global().getPropertyAsFunction(runtime, "Boolean");
   return Boolean.call(runtime, value).getBool();
 }
+
+void objectAssign(
+    jsi::Runtime& runtime,
+    jsi::Object& target,
+    const jsi::Object& value) {
+  auto Object = runtime.global().getPropertyAsObject(runtime, "Object");
+  auto assign = Object.getPropertyAsFunction(runtime, "assign");
+  assign.callWithThis(runtime, Object, target, value);
+}
 } // namespace
 
 namespace facebook::react {
@@ -199,8 +208,14 @@ void JsErrorHandler::emitError(
     message += ", js engine: " + stringifyToCpp(runtime, jsEngineValue);
   }
 
-  // TODO: What about spreading in decoratedExtraDataKey?
+  auto extraDataKey = jsi::PropNameID::forUtf8(runtime, "RN$ErrorExtraDataKey");
+  auto extraDataValue = errorObj.getProperty(runtime, extraDataKey);
+
   auto extraData = jsi::Object(runtime);
+  if (extraDataValue.isObject()) {
+    objectAssign(runtime, extraData, extraDataValue.asObject(runtime));
+  }
+
   extraData.setProperty(runtime, "jsEngine", jsEngineValue);
   extraData.setProperty(runtime, "rawStack", error.getStack());