Convert all the integer value to string in JSON

My JSON string is:

{name:"MyNode", width:200, height:100}

I want to change it to:

{name:"MyNode", width:"200", height:"100"}

so that all integer values become strings

My main code is:

{
     "firstName": "John",
     "lastName": "Smith",
     "age": 25,
     "address":
     {
         "streetAddress": "21 2nd Street",
         "city": "New York",
         "state": "NY",
         "xy": 10021
     },
     "IDNumber":
     [
         {
           "type": "home",
           "number": 1234
         },
         {
           "type": "fax",
           "number": 4567
         }
     ]
 }

I need all integer values become strings