Parse nested object in JSON string

I have this code:

let test = '{"attribute_as":"plan_id","operator":"fromTo","values":"{"from":"70","to":"80"}"}';
console.log(JSON.parse(test));

It of course fail because in values I have an object. Is there any option how to parse this string in easy way? Or is it not possible at all?

At the end the result should be:

{
    attribute_as: 'plan_id',
    operator: 'fromTo',
    values: {
        from: 70,
        to: 80
    }
}

Answer

The string is incorrect:

let err = '{"attribute_as":"plan_id","operator":"fromTo","values":"{"from":"70","to":"80"}"}';
// This is the original string
let pass = '{"attribute_as":"plan_id","operator":"fromTo","values":{"from":70,"to":80}}';
// Corrected string

let desiredObj = {
    attribute_as: 'plan_id',
    operator: 'fromTo',
    values: {
        from: 70,
        to: 80
    }
};

console.log(JSON.stringify(desiredObj) == err);
console.log(JSON.stringify(desiredObj) == pass);