Deep equal - data structures object, eloquent javascript

deepEqual.js

function deepEqual(a, b) {
	var
    	isAobj = (typeof a === 'object'),
        isBobj = (typeof b === 'object'),
        isABobjs = (isAobj && isBobj),
        out = (a === b);
  
  	function checkX (x) {
	      var
	      	ix,
	        res;
	      
	      for ( ix in x ) {
	        if ( x.hasOwnProperty(ix) ) {
	        	res = deepEqual( a[ix], b[ix]);
	        }
	        if ( !res ) {
	        	break;
	        }
	      }
	      
	      return res;
  	}
  
	if ( a && b && isABobjs && !out ) {
		out = checkX(a) && checkX(b);
	}
  
  	return out;
}