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()
