How to add a line to Json in Javascript Node.js program

I am trying to make a command for my Discord bot that when you do a cmd like

]scriptadd (NAME) (PASTEBIN)

that it will add a name and pastebin to the line, like this:

before

{"NAME" : "PASTEBIN"}

after

{"NAME" : "PASTEBIN", "NAME2", "PASTEBIN"}

How would I do this with my json file and add the line after I do? I want it to essentiall keep adding without me needing to go in and make a variable with the code

via Anonymous