gistfile1.js

var app = (function(testMode) {
  
  //Private methods
  var method1 = function() {};
  var method2 = function() {};
  
  //Public methods
  var method3 = function() {};
  var method4 = function() {};  
  
  if (!testMode) {
    return {
      method3: method3,
      method4: method4
    };
  } else {
    return {
      method1: method1,
      method2: method2,
      method3: method3,
      method4: method4
    };   
  }
  
})(testMode);