[рони]

ibmpclp,

<script>
let list = {
    value: 1,
    next: {
      value: 2,
      next: {
        value: 3,
        next: {
          value: 4,
          next: null
        }
      }
    }
  };

  function printList(list) {
  var a = [list.value];
    if (list.next) {
      a = printList(list.next).concat(a);
    }
   return a
  }
  var a =  printList(list);
  document.write(JSON.stringify(a, null, 4))
  </script>