How to determine if a function has been called without setting global variable

Question

I am looking for a good technique to get away from what I am tempted to do: to set a global variable.

The first time someone runs a function by clicking a button it triggers an initial function to turn a few things into draggables. Later, if they click the button a second time I want to determine if the init function has been initialized, and if so to not call it again. I could easily do this by setting a global variable from the init function and then checking that variable from the click function, but I'm wondering how to do this without setting a global variable. I would really like an example of a way to do this.

Answer 1

You could add a property to the function:

function init() {     init.called = true; }  init();  if(init.called) {     //stuff } 

Answer 2

While @Levi's answer ought to work just fine, I would like to present another option. You would over write the init function to do nothing once it has been called.

var init = function () {    // do the initializing      init = function() {         return false;     } }; 

The function when called the first time will do the init. It will then immediately overwrite itself to return false the next time its called. The second time the function is called, the function body will only contain return false.

For more reading: http://www.ericfeminella.com/blog/2011/11/19/function-overwriting-in-javascript/