Can I use variable get Json value in javascript?

Question

Can I use variable get Json value in javascript?
myJSON：

    const json={
     Louis:{
       age:3,
     },
     Kitty:{
       age:10,
     }
    }

I want to use this get my Json

var name="Louis";
const putJson=()=>{
 json.name.age=10;
}

How can i do?