Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.
Example:
Input: 1->2->4, 1->3->4
Output: 1->1->2->3->4->4 var mergeTwoLists = function(l1, l2) { if( l1.length === 0 ) { return l2; } else if(l2.length === 0) { return l1; } else { var l3 = l1.concat(l2).sort(); return l3; } };