linked-list.js

function LinkedList() {
  var Node = function(element) {
    this.element = element;
    this.next = null;
  };

  var length = 0;
  var head = null;

  this.append = function(element) {
    var node = new Node(element),
        current;

        if(head === null) {
          head = node;
        } else {
          current = head;

          // loop the list until we find the last item
          while(current.next) {
            current = current.next;
          }

          // get the last item and assign next to node to make the LinkedList
          current.next = node;
        }

        length++;
  };
  this.insert = function(position, element) {
    // check for out-of-bounds values
    if (position >= 0 && position <= length) {

      var node = new Node(element),
          current = head,
          previous,
          index = 0;

      if (position === 0) {
        node.next = current;
        head = node;
      } else {
        while (index++ < position) {
          previous = current;
          current = current.next;
        }

        node.next = current;
        previous.next = node;

      }

      length++;

      return true;
    } else {
      return false;
    }
  };
  this.removeAt = function(element) {

    // check for out-of-bounds values
    if (position > -1 && position < length) {
      var current = head,
          previous,
          index = 0;

      // removing the first item
      if (position === 0) {
        head = current.next;
      } else {

        while (index++ < position) {
          previous = current;
          current = current.next;
        }

        // link previous with /current/s next: skip it to remove
        previous.next = current.next;
      }

      length--;

      return current.element;
    } else {
      return null;
    }
  };
  this.remove = function(element) {
    var index = this.indexOf(element);
    return this.removeAt(index);
  };
  this.indexOf = function(element) {

    var current = head,
        index = -1;

    while (current) {
      if (element === current.element) {
        return index;
      }
      index++;
      current = current.next;
    }

    return -1;
  };
  this.isEmpty = function() {
    return length === 0;
  };
  this.size = function() {
    return length;
  };
  this.toString = function() {
    var current = head,
        string = '';

    while (current) {
      string = current.element;
      current = current.next;
    }
    return string;
  };
  this.getHead = function() {
    return head;
  };
  this.print = function() {

  };
}