Project2

class DoublyLinkedList {
  constructor(value) {
    this.head = {
      value: value,
      next: null,
      prev: null
    };
    this.tail = this.head;
    this.length = 1;
  }
  append(value) {
    const newNode = {
      value: value,
      next: null,
      prev: null
    }
    console.log(newNode)
    newNode.prev = this.tail
    this.tail.next = newNode;
    this.tail = newNode;
    this.length++;
    return this;
  }
  prepend(value) {
    const newNode = {
      value: value,
      next: null,
      prev: null
    }
    newNode.next = this.head;
    this.head.prev = newNode
    this.head = newNode;
    this.length++;
    return this;
  }
  printList() {
    const array = [];
    let currentNode = this.head;
    while(currentNode !== null){
      array.push(currentNode.value)
      currentNode = currentNode.next
    }
    console.log(array);
  }
  insert(index, value){
    //Check for proper parameters;
    if(index >= this.length) {
      return this.append(value);
    }
    
    const newNode = {
      value: value,
      next: null,
      prev: null
    }
    const leader = this.traverseToIndex(index-1);
    const follower = leader.next;
    leader.next = newNode;
    newNode.prev = leader;
    newNode.next = follower;
    follower.prev = newNode;
    this.length++;
    console.log(this)
    return this.printList();
  }
  traverseToIndex(index) {
    //Check parameters
    let counter = 0;
    let currentNode = this.head;
    while(counter !== index){
      currentNode = currentNode.next;
      counter++;
    }
    return currentNode;
  }
  remove(index){
      const leader=this.traverseToIndex(index-1);
      const unwantedNext=leader.next;
      const unwantedPrev=unwantedNext.prev;
      leader.next=unwantedNext.next;
      leader.next.prev=unwantedPrev;
      this.length--;
      return this.printList();
  }
}

let myLinkedList = new DoublyLinkedList(10);
myLinkedList.append(5)
myLinkedList.append(16)
myLinkedList.prepend(1)
myLinkedList.insert(2, 99)
myLinkedList.insert(20, 88)
myLinkedList.printList()
myLinkedList.remove(2)
myLinkedList.printList()