JQuery add-on that add an If statement

jquery_if_then.js

//JQuery add-on that add an If statement
$.fn.ift = function(){
    var flag = arguments[0];
    var func = arguments[1];
    var else_func = arguments[2];

    if(flag && $.isFunction(func)){
        func.call(this, this);
    }else if(!flag && $.isFunction(else_func)){
        else_func.call(this, this);
    }
    return this;
}
/*
example.
$('body')
  .ift(true, function(){$(this).css('background-color','blue')} )
  .ift((1!=1), function(){$(this).css('background-color','gray')} )
  .ift(
    some.isValid(),
    function(){$(this).css('background-color','green')},
    function(){$(this).css('background-color','red')}
   );

also, coffeescript.
$('<span />')
  .ift(
    src.pin==1
    ()-> $(this).addClass('check').text('!') # then
    ()-> $(this).addClass('nocheck').text('-') #else
  )
*/