#include #include using json = nlohmann::json; using json_editable_document = nlohmann::json_editable_document; using json_editable_view = nlohmann::json_editable_view; int main() { // a deprecated field is dropped from a configuration file, and a // decommissioned replica is removed from the list -- "price" keeps its // trailing zero, and the fields around the removed ones keep their order const std::string text = R"({ "name": "cache", "legacy_host": "db0", "host": "db1", "price": 19.90, "replicas": ["db2", "db3", "db4"] })"; json_editable_document doc = json_editable_document::parse(text); doc.erase(doc.root(), "legacy_host"); // (1) an object member doc.erase(doc.root()["replicas"], 1); // (2) an array element ("db3") const std::size_t removed = doc.erase(json::json_pointer("/replicas/0")); // (3) via a JSON pointer std::cout << removed << '\n'; std::cout << doc.root().dump(2, ' ', false, json_editable_view::number_format::source) << "\n\n"; // the same edits on a plain json value: object_t is a std::map, so // parsing already sorted the keys, and dump() rewrites every number to // its shortest form, even "price", which was never touched json plain = json::parse(text); plain.erase("legacy_host"); plain["replicas"].erase(1); plain["replicas"].erase(0); std::cout << plain.dump(2) << '\n'; }