Javascript Data Structure List Linked List 3

var LinkedList = function() {
  this.head = null;//from  w  w  w. java  2  s  .  c o  m
};

LinkedList.prototype = {
  insert: function(data) {
    console.log("calling insert(" + data + ")");
    var node = {
      data: data,
      next: null
    };
    if (this.head === null) {
      this.head = node;
    }
    else {
      var currNode = this.head;
      while (currNode.next !== null) {
        currNode = currNode.next;
      }
      currNode.next = node;
    }
    return this.head;
  },
  delete: function(index) {
    console.log("calling delete(" + index + ")");
    var currNode = this.head;
    var previous = {};
    if (index >= 0) {
      if (index === 0) {
        this.head = this.head.next;
        return this.head;
      }
      else {
        for (var i = 1; i <= index; i++) {
          if (currNode.next === null) {
            return null;
          }
          previous = currNode;
          currNode = currNode.next;
        }
        previous.next = currNode.next;
        return currNode;
      }
    }
    else {
      return null;
    }

  },
  print: function() {
    var results = [];
    var currNode = this.head;
    //while last.next != null
    while (currNode) {
      results.push(currNode.data);
      currNode = currNode.next;
    }
    console.log(results);
  }
};

var ll = new LinkedList();
console.log(ll.insert("hello"));
//  -> {data: "hello", next: null}
console.log(ll.insert("class"));
//  -> {data: "hello", next: {data: "class", next: null}}
console.log(ll.delete(1));

//  -> {data: "hello", next: null}
console.log(ll.insert("world"));
//  -> {data : "hello", next: {data: "world", next: null}}
ll.print();