Remove quotes from field value in json, convert string to number

I have a field in the JSON that's pulled as string and I need to have it showing as a number in the JSON.

Original:

"productId": "1378427812",

Desired:

"productId": 1378427812,

During the mapping, when I change the Field Type to Number, it returns a cero in the value field.

any update on this?

This is not needed anymore, I've accomplish this with a script, but couldn't find a way to do it using the mapping settings