Question

I have this json object:

values: {
    username: { type: String, unique: true },
    password: { type: String }
}

When running JSON.stringify(values) I get:

{"username":{"unique":true},"password":{}}

It omits type: String.

Any workarounds?

Answer 1

JSON.stringify omits values that are not valid JSON, including undefined and Function.

If you really really want to, you could use the replacer parameter (not sure how cross-browser this will be though) and work around this. This function will basically inspect to see if the value is a function, and it will return the function name. In your example, it will return "String", since String is a global constructor function.

JSON.stringify(your_object, function (key, value) {
    if (typeof value === "function") {
        return value.name; // or value.toString() for the function body/declaration
    }

    return value;
});

Although, to be clear, you’re better off using a string as your type, ("String" instead of String) no hoops to jump through then.