understanding shorthand document.ready

understanding shorthand document.ready

hello guys , i just have a simple jquery question , now look at the function  below :: 


  1. (function(){

  2.     console.log('hello');
  3.   
  4. })();
its a very simple IIFE now the jquery document.ready has a very simple and similar shorthand , like so :: 

  1. $(function(){

  2.     console.log('hello');
  3.   
  4. })();
just the dollar in the beginning , now how does .  

  1. $(document).ready(function(){});

ever turn into 

  1. $(function(){  });

Thank you. 

Gautam.