Reduced module config data

Summary: public

We're sending a lot of module config data when the app first starts, and much of this is redundant.

UIExplorer current sends 19061 bytes of module config JSON. This diff reduces that to 16104 (15% saving) by stripping modules that have no methods or constants, and removing method types unless method is async.

Reviewed By: tadeuzagallo, javache

Differential Revision: D2570010

fb-gh-sync-id: 8c0abbd1cdee3264b37a4f52e852008caaffb9c5

Author: nicklockwood

Libraries/Utilities/MessageQueue.js

@@ -186,7 +186,7 @@ class MessageQueue {
     let moduleNames = Object.keys(localModules);
     for (var i = 0, l = moduleNames.length; i < l; i++) {
       let moduleName = moduleNames[i];
-      let methods = localModules[moduleName].methods;
+      let methods = localModules[moduleName].methods || {};
       let moduleID = localModules[moduleName].moduleID;
       moduleTable[moduleID] = moduleName;
       methodTable[moduleID] = {};
@@ -210,12 +210,16 @@ class MessageQueue {
   }
 
   _genModule(module, moduleConfig) {
-    let methodNames = Object.keys(moduleConfig.methods);
+    let methods = moduleConfig.methods || {};
+    let methodNames = Object.keys(methods);
     for (var i = 0, l = methodNames.length; i < l; i++) {
       let methodName = methodNames[i];
-      let methodConfig = moduleConfig.methods[methodName];
+      let methodConfig = methods[methodName];
       module[methodName] = this._genMethod(
-        moduleConfig.moduleID, methodConfig.methodID, methodConfig.type);
+        moduleConfig.moduleID,
+        methodConfig.methodID,
+        methodConfig.type || MethodTypes.remote
+      );
     }
     Object.assign(module, moduleConfig.constants);
     return module;
@@ -260,7 +264,7 @@ class MessageQueue {
 
 }
 
-function createErrorFromErrorData(errorData: ErrorData): Error {
+function createErrorFromErrorData(errorData: {message: string}): Error {
   var {
     message,
     ...extraErrorInfo,

React/Base/RCTBatchedBridge.m

@@ -310,7 +310,10 @@ - (NSString *)moduleConfig
 {
   NSMutableDictionary *config = [NSMutableDictionary new];
   for (RCTModuleData *moduleData in _moduleDataByID) {
-    config[moduleData.name] = moduleData.config;
+    NSDictionary *moduleConfig = moduleData.config;
+    if (moduleConfig) {
+      config[moduleData.name] = moduleConfig;
+    }
     if ([moduleData.instance conformsToProtocol:@protocol(RCTFrameUpdateObserver)]) {
       [_frameUpdateObservers addObject:moduleData];
 

React/Base/RCTModuleData.m

@@ -81,6 +81,10 @@ - (NSArray *)methods
 
 - (NSDictionary *)config
 {
+  if (_constants.count == 0 && self.methods.count == 0) {
+    return nil; // Nothing to export
+  }
+
   NSMutableDictionary *config = [NSMutableDictionary new];
   config[@"moduleID"] = _moduleID;
 
@@ -90,12 +94,20 @@ - (NSDictionary *)config
 
   NSMutableDictionary *methodconfig = [NSMutableDictionary new];
   [self.methods enumerateObjectsUsingBlock:^(id<RCTBridgeMethod> method, NSUInteger idx, __unused BOOL *stop) {
-    methodconfig[method.JSMethodName] = @{
-      @"methodID": @(idx),
-      @"type": method.functionType == RCTFunctionTypePromise ? @"remoteAsync" : @"remote",
-    };
+    if (method.functionType == RCTFunctionTypePromise) {
+      methodconfig[method.JSMethodName] = @{
+        @"methodID": @(idx),
+        @"type": @"remoteAsync",
+      };
+    } else {
+      methodconfig[method.JSMethodName] = @{
+        @"methodID": @(idx),
+      };
+    }
   }];
-  config[@"methods"] = [methodconfig copy];
+  if (methodconfig.count) {
+    config[@"methods"] = [methodconfig copy];
+  }
 
   return [config copy];
 }