gistfile1.js

var app = {
  before: function () { console.log("i am going to be runned before all other functions") },

  func1: function () {
    console.log("func1");
  },

  func2: function () {
    console.log("func2");
  }
};

for (var func in app) {
	if (app.hasOwnProperty(func) && func != 'before') {
		var oldfunc = app[func];
		app[func] = function () {
			app.before();
			oldfunc();
		}
	}
}

app.func1();
// i am going to be runned before all other functions
// func1

app.func2();
// i am going to be runned before all other functions
// func2