Method dropNullPlaceholders

external/jsoncpp/jsoncpp.cpp:3234–3234

void FastWriter::enableYAMLCompatibility() { yamlCompatiblityEnabled_ = true; }

void FastWriter::dropNullPlaceholders() { dropNullPlaceholders_ = true; }

void FastWriter::omitEndingLineFeed() { omitEndingLineFeed_ = true; }