Why (function($){…})(jQuery)?

Question

JavaScript

Why is it customary to write:

(function($) {
  $.fn.mySimplePlugin = function(){
     // код плагина ...
     return this;
  };
})(jQuery);

But not:

$.fn.mySimplePlugin = function($){
     // код плагина ...
     return this;
  };

Google says that the first option will isolate the $ and allow this to be returned. But the other one does it too. But it's also shorter.

Answer 1

The (function($){…})(jQuery) construct isolates the plugin's namespace. This is a guarantee that the plugin will not overwrite someone else's variable, for example.

Answer 2

To shut up the holey scope model in JS.
In modern JS, this is not necessary: ​​modules and let fixed the problem.