Refer One Json's Properties Into Another Json

There is a file with a JSON with some properties. There is another file with a json. Properties from one json file have to be used in another json file. You have to show how to write the first json file with properties included from second json file and how to actually populate it with those properties on extracting the json from that file. file1 { "key1" : "value1", "key2" : [login to view URL]'s value (how to write this in file here?) } file2 { "key1": "value1" } file1's json should finally become - { "key1" : "value1", "key2" : "value1" }