config.js

/**
 * Module dependencies.
 */

var pkg = require('../package');
var env = process.env.NODE_ENV || 'development';

/**
 * Return setting `name`.
 *
 * @param {String} name
 * @return {Mixed}
 * @api public
 */

module.exports = function(name){
  if (null == pkg[env]) throw new Error('invalid configuration environment "' + env + '"');
  if (null == pkg[env][name]) throw new Error('invalid configuration key "' + name + '"');
  return pkg[env][name];
};

assume production would be safer as far as precedence goes, I've found throwing extremely helpful, little typos in config etc go undetected, it would have to be a pretty massive fail to have that throw in production, so unless you don't write tests or use your app at all it's fine