This is the json object I am working with
{ \"name\": \"John Smith\", \"age\": 32, \"employed\": true, \"address\": {
Just convert the JSON string to an object using JSON.parse() and then add the property. If you need it back into a string, do JSON.stringify().
JSON.parse()
JSON.stringify()
BTW, there's no such thing as a JSON object. There are objects, and there are JSON strings that represent those objects.