v8 c ++ – 如何获取作为参数提供的对象键值

我将js对象传递给我的函数

myFunc.do({'1':2}); 

我想std::cout从我的对象在c + +中的键值对

这是我的

 Handle<Object> object = Handle<Object>::Cast(args[i]); Local<Array> objArray = object->GetPropertyNames(); for(uint o=0; o < objArray->Length(); o++) { Local<Value> val = objArray->Get(o); v8::String::Utf8Value str(val->ToString()); std::string foo = std::string(*str); std::cout << "val is= " << foo; } return; 

我做错了object->GetPropertyNames(); ，因为它没有得到我传递的值

更新这里是另一个无用的尝试

 Local<Context> context = isolate->GetCurrentContext(); Local<Object> object = Local<Object>::Cast(args[i]); Local<Array> props; if (!object->GetOwnPropertyNames(context).ToLocal(&props)) { std::cout << "Error"; return; } for (uint32_t p = 0; p < props->Length(); ++p) { Local<Value> name; Local<Value> property_value; props->Get(context, p).ToLocal(&name); v8::String::Utf8Value str(name->ToString()); std::string foo = std::string(*str); std::cout << "val is= " << foo; // outputs 0 } 

感谢帮助

Answer 1

在节点7上testing的一个可validation的例子也应该在6和4上工作，对于其他版本的节点，你可能需要nan ：

 // logger.cc #include <string> #include <iostream> #include <node.h> namespace demo { using v8::Context; using v8::Function; using v8::FunctionCallbackInfo; using v8::FunctionTemplate; using v8::Isolate; using v8::Local; using v8::Number; using v8::Object; using v8::Persistent; using v8::String; using v8::Value; using v8::Array; using v8::Exception; // Logging function for objects void Log(const FunctionCallbackInfo<Value>& args) { Isolate* isolate = args.GetIsolate(); if(args.Length() < 1 || !args[0]->IsObject()) { isolate->ThrowException(Exception::TypeError( String::NewFromUtf8(isolate, "Error: One object expected"))); return; } Local<Context> context = isolate->GetCurrentContext(); Local<Object> obj = args[0]->ToObject(context).ToLocalChecked(); Local<Array> props = obj->GetOwnPropertyNames(context).ToLocalChecked(); for(int i = 0, l = props->Length(); i < l; i++) { Local<Value> localKey = props->Get(i); Local<Value> localVal = obj->Get(context, localKey).ToLocalChecked(); std::string key = *String::Utf8Value(localKey); std::string val = *String::Utf8Value(localVal); std::cout << key << ":" << val << std::endl; } } void CreateFunction(const FunctionCallbackInfo<Value>& args) { Isolate* isolate = args.GetIsolate(); Local<FunctionTemplate> tpl = FunctionTemplate::New(isolate, Log); Local<Function> fn = tpl->GetFunction(); // omit this to make it anonymous fn->SetName(String::NewFromUtf8(isolate, "loggerFunction")); args.GetReturnValue().Set(fn); } void Init(Local<Object> exports, Local<Object> module) { NODE_SET_METHOD(module, "exports", CreateFunction); } NODE_MODULE(logger, Init) } // namespace demo 

绑定：

 { "targets": [ { "target_name": "logger", "sources": [ "logger.cc" ] } ] } 

testing：

 const logger = require('./build/Release/logger'); var log = logger(); log({'Cave' :'Johnson'}); log({'1':2}); log({a: 1}); 

输出：

 Cave:Johnson 1:2 a:1 

Answer 2

这是我的实现：

 void do_handler(const FunctionCallbackInfo<Value>& args) { Isolate* isolate = args.GetIsolate(); if (args.Length() < 1 && !args[0]->IsObject()) { isolate->ThrowException(Exception::TypeError( String::NewFromUtf8(isolate, "Wrong arguments: object expected"))); return; } auto obj = args[0]->ToObject(isolate); Local<Array> props = obj->GetOwnPropertyNames(); for (uint32_t i = 0; i < props->Length(); ++i) { const Local<Value> key_local = props->Get(i); const Local<Value> val_local = obj->Get(key_local); std::string key = *String::Utf8Value(key_local); std::string val = *String::Utf8Value(val_local); std::cout << "\"" << key << "\"" << ": \"" << val << "\"" << std::endl; } }