Mapbox nested json

Question

I want to paint a mapbox map based on a nested property. Property is stored as a JSON string in mapbox studio. My property object looks like this :

{
    "foo": {
        "bar": {
            "value1": 1,
            "value2": 2
        }
    }
}

I want for example to paint a polygon based on foo.bar.value1

What are the best practices for this, should I flatten the json in properties ?

Thanks.