What is the problem this feature will solve?

Using Node-API, I would like my C/C++ addon to generate a JavaScript object decorated with a tag name, like this:

const obj = {
  name: "john",
  [Symbol.toStringTag]: "MyTag"
};

So I can get:

I believe this is not possible to set the Symbol.toStringTag property to an object created with the current Node-API.

What is the feature you are proposing to solve the problem?

I guess we need access to the global Symbol.toStringTag and other well-known Symbols defined in JavaScript.
Below is the Node.js example to create a new Symbol and set it as a property for an object (along other properties):

Instead of creating a new Symbol we would have to use the existing Symbol.toStringTag.
Maybe you could consider to have a method like napi_get_symbol_tostringtag(env, &name_symbol) to replace napi_create_symbol(.. used on line 78.

What alternatives have you considered?

Explored the Node-API but I have no clue for a workaround in the C/C++ code.

For a root object returned by the add-on, one may use the add-on main.js file to add the property dynamically in JavaScript before the export, but it's not pretty.