dotconf | : ring : One file , to rule | Automation library

i have the same web application running in two different environment in different servers and conecting to 2 diffrent databases. and i have one config.json file contain all the connection information of the two databases.

in dev in the app.js file and database/db.js i call a require the file getConf which call config.json with preprod object, in the production i change it to prod

i would like to do this automaticcaly wich mean for the update of the production i dont change any file just a copy paste from the dev but it detect automatically the environment and set the appropriate database.

i tried many modules like nconf dotconf and config but all require to select the environement in the command line before lanching the app but my 2 apps are running in two different IIS servers in my company servers and they are lunched from iis and not from the command line

var config = require('./database/getConf').preprod // or prod

i hope doing just a copy paste of the hole project folder from thedev to the prod