I have a Json string like this:

 var json =     "[{"Id":"1234",
        "FirstName":"One",    
        "Index":"32",
        "Type":"t1",
        "Children":[{"Id":"976","FirstName":"Two","Index":"32","Type":"t2",     

           "Children":[{"Id":"428",
               "FirstName":"Three",            
               "Index":"32",
               "Type":"t3",
               "Children":[],
               "ParentId":"f235"}],        
               
        "ParentId":"f826"}],
     "ParentId":"0000"}]"

I want to create a number of objects with only the fields Id,FirstName,Children, not Index and Type. Each Object has a number of child Services as well.

So obj1 will have properties Firstname, ParentId and Children and if you drill down to its Children it will have another object with Id , firstname , ParentId , and for this if we drill down there are no more Children

I began by doing something like 
    
    var servicejson = JSON.parse(jsonStr);
     for (let i = 0; i < servicejson).length; i++) {
            var parentnode = {
                Id: servicejson[i].Id,
                FirstName: servicejson[i].JsonValue,        
                ParentId: servicejson[i].ParentId,             
            };        
            
            //check if children
            if (servicejson[i].Children.length > 0) {
                //do something here ??
            }
    }
    

There will be one Object and within that will be a Child , and withing that Child there is another Child node. I got stuck assigning these to the Object or pushing onto an array on the Object as I assume it may need a recursive call to assign the Children array and this is where i need some help Any ideas on how I can to do this ?