My team have a code review for using your json library, but the rules are really......

[ly5519]

our object no exception, so must be checked before use, like this:

nlohmann::json json;
if (json[KEY_DEV_ID].is_string()) {
    std::string str = json[KEY_DEV_ID].get<std::string>();
    dosomething();
    // ......
}

but rules say I should:

nlohmann::json json;
if (json.contains(KEY_DEV_ID) && json[KEY_DEV_ID].is_string()) {
    std::string str = json[KEY_DEV_ID].get<std::string>();
    dosomething();
    // ......
}

this may look not bad, how about this?🤣

nlohmann::json json;
if (json.contains(KEY_DATA) && json[KEY_DATA].is_object() &&
    json[KEY_DATA].contains(HANDSHANKE_DATA) && json[KEY_DATA][HANDSHANKE_DATA].is_object() &&
    json[KEY_DATA][HANDSHANKE_DATA].contains(KEY_DEV_ID) && json[KEY_DATA][HANDSHANKE_DATA][KEY_DEV_ID].is_string()) {
    std::string str = json[KEY_DATA][HANDSHANKE_DATA][KEY_DEV_ID].get<std::string>();
    dosomething();
    // ......
}

I think only need the last one, like this:

nlohmann::json json;
if (json[KEY_DATA][HANDSHANKE_DATA][KEY_DEV_ID].is_string()) {
    std::string str = json[KEY_DATA][HANDSHANKE_DATA][KEY_DEV_ID].get<std::string>();
    dosomething();
    // ......
}

Is it right, is it really necessary?

help me！thank you😘