Implicit conversion causes "cannot use operator[] with a string argument with string"

[tawmoto]

• What is the issue you have?
  I get an exception when I do an implicit conversion and then read a value.
  I read here that json = string should work.

• Please describe the steps to reproduce the issue. Can you provide a small but working code example?

using json = nlohmann::json;
string str = R"({"happy": true,"pi": 3.141})";

// if I replace it with "json js = json::parse(str.c_str());", it works!		
json js = str;

// this returns ""[json.exception.type_error.305] cannot use operator[] with a string argument with string"
auto v1 = js["happy"].get<bool>();

• Which compiler and operating system are you using? Is it a supported compiler?
  VS2017

• Did you use a released version of the library or the version from the develop branch?
  develop, tried also the latest release and happens also

Maybe I am doing something wrong? I am evaluating this project to replace cjson and I hope that I will make the switch. 👍
Thank you

[nlohmann]

By calling json js = str;, you are not parsing the string to a JSON value, but create a JSON value that holds that string. For that reason, calling js["happy"] makes no sense, as js is a string and not an object, hence the exception.

The README says that you can do the following:

// create a JSON value from a string
json j = "Hello";

// create a string from a JSON value
string s = j;

[tawmoto]

I see, so I will just use the "parse()" function then.
Thank you