RN 调 js 核心代码

^{
RCTJSCExecutor *strongSelf = weakSelf;
if (!strongSelf || !strongSelf.isValid) {
return;
}
NSError *error;

JSValueRef errorJSRef = NULL;
JSValueRef resultJSRef = NULL;
RCTJSCWrapper *jscWrapper = strongSelf->_jscWrapper;
JSGlobalContextRef contextJSRef = jscWrapper->JSContextGetGlobalContext(strongSelf->_context.ctx);
JSContext *context = strongSelf->_context.context;
JSObjectRef globalObjectJSRef = jscWrapper->JSContextGetGlobalObject(strongSelf->_context.ctx);

// get the BatchedBridge object
JSValueRef batchedBridgeRef = strongSelf->_batchedBridgeRef;
if (!batchedBridgeRef) {
  JSStringRef moduleNameJSStringRef = jscWrapper->JSStringCreateWithUTF8CString("__fbBatchedBridge");
  batchedBridgeRef = jscWrapper->JSObjectGetProperty(contextJSRef, globalObjectJSRef, moduleNameJSStringRef, &errorJSRef);
  jscWrapper->JSStringRelease(moduleNameJSStringRef);
  strongSelf->_batchedBridgeRef = batchedBridgeRef;
}

if (batchedBridgeRef != NULL && errorJSRef == NULL && !jscWrapper->JSValueIsUndefined(contextJSRef, batchedBridgeRef)) {
    //RN调JS的核心代码
    NSLog(@"test1");
  // get method
  JSStringRef methodNameJSStringRef = jscWrapper->JSStringCreateWithCFString((__bridge CFStringRef)method);
  JSValueRef methodJSRef = jscWrapper->JSObjectGetProperty(contextJSRef, (JSObjectRef)batchedBridgeRef, methodNameJSStringRef, &errorJSRef);
  jscWrapper->JSStringRelease(methodNameJSStringRef);

  if (methodJSRef != NULL && errorJSRef == NULL && !jscWrapper->JSValueIsUndefined(contextJSRef, methodJSRef)) {
    JSValueRef jsArgs[arguments.count];
    for (NSUInteger i = 0; i < arguments.count; i++) {
      jsArgs[i] = [jscWrapper->JSValue valueWithObject:arguments[i] inContext:context].JSValueRef;
    }
      NSLog(@"test2 ");
    resultJSRef = jscWrapper->JSObjectCallAsFunction(contextJSRef, (JSObjectRef)methodJSRef, (JSObjectRef)batchedBridgeRef, arguments.count, jsArgs, &errorJSRef);
  } else {
    if (!errorJSRef && jscWrapper->JSValueIsUndefined(contextJSRef, methodJSRef)) {
      error = RCTErrorWithMessage([NSString stringWithFormat:@"Unable to execute JS call: method %@ is undefined", method]);
    }
  }
} else {
  if (!errorJSRef && jscWrapper->JSValueIsUndefined(contextJSRef, batchedBridgeRef)) {
    error = RCTErrorWithMessage(@"Unable to execute JS call: __fbBatchedBridge is undefined");
  }
}

if (errorJSRef || error) {
  if (!error) {
    error = RCTNSErrorFromJSError(jscWrapper, contextJSRef, errorJSRef);
  }
  onComplete(nil, error);
  return;
}

// Looks like making lots of JSC API calls is slower than communicating by using a JSON
// string. Also it ensures that data stuctures don't have cycles and non-serializable fields.
// see [RCTJSCExecutorTests testDeserializationPerf]
id objcValue;
// We often return `null` from JS when there is nothing for native side. JSONKit takes an extra hundred microseconds
// to handle this simple case, so we are adding a shortcut to make executeJSCall method even faster
if (!jscWrapper->JSValueIsNull(contextJSRef, resultJSRef)) {
  objcValue = [[jscWrapper->JSValue valueWithJSValueRef:resultJSRef inContext:context] toObject];
}

onComplete(objcValue, nil);}

精简

RCTJSCWrapper *jscWrapper = strongSelf->_jscWrapper;
// get method
JSValueRef jsArgs[arguments.count];
for (NSUInteger i = 0; i < arguments.count; i++) 
{
  jsArgs[i] = [jscWrapper->JSValue valueWithObject:arguments[i] inContext:context].JSValueRef;
}
resultJSRef = jscWrapper->JSObjectCallAsFunction(contextJSRef, (JSObjectRef)methodJSRef, (JSObjectRef)batchedBridgeRef, arguments.count, jsArgs, &errorJSRef);
id objcValue;
objcValue = [[jscWrapper->JSValue valueWithJSValueRef:resultJSRef inContext:context] toObject];
onComplete(objcValue, nil);

精简
jscWrapper->JSObjectCallAsFunction

JavaScriptCore：JSObjectRef
JS_EXPORT JSValueRef JSObjectCallAsFunction(JSContextRef ctx, JSObjectRef object, JSObjectRef thisObject, size_t argumentCount, const JSValueRef arguments[], JSValueRef* exception);