How can I add string pairs to a document of rapidjson

If #define RAPIDJSON_HAS_STDSTRING 1 (before including rapidjson header files, or defined in compiling flags), there are some extra APIs for std::string.

To make "copy-strings" (allocated duplicates of source strings) of std::string, you can use constructor with allocator:

for (auto& pair : map) {    rapidjson::Value key(pair.first, allocator);    rapidjson::Value value(pair.second, allocator);    doc.AddMember(key, value, allocator);}

Or make it a single statement:

for (auto& pair : map)    doc.AddMember(        rapidjson::Value(pair.first, allocator).Move(),        rapidjson::Value(pair.second, allocator).Move(),        allocator);

If you presume that the lifetime of strings are longer than doc, then you can use "const-string" instead, which is simpler and more efficient:

for (auto& pair : map)    doc.AddMember(        rapidjson::StringRef(pair.first),        rapidjson::StringRef(pair.second),        allocator);

I think the macro RAPIDJSON_HAS_STDSTRING should be documented better...

Now, I realise that I have made 2 mistake:
1. I should invoke doc.SetObject(); after doc is created.
2. How to create string in rapidjson.

Document doc;doc.SetObject();auto& allocator = doc.GetAllocator();rapidjson::Value s;s = StringRef(className.c_str());doc.AddMember("className", s, allocator);auto& map = sprite->toJson();for (auto& pair : map) {    rapidjson::Value key(pair.first.c_str(), pair.first.size(), allocator);    rapidjson::Value value(pair.second.c_str(), pair.second.size(), allocator);    doc.AddMember(key, value, allocator);}

There should be some better way to do it.