reverseLinkedList.js

// add a method reverse() to the linked list that reverses the entire list of nodes

class LinkedList {
    constructor(value) {
      this.head = {
        value: value,
        next: null,
      };
      this.tail = this.head;
      this.length = 1;
    }
    append(value) {
      const newNode = {
        value: value,
        next: null,
      };
      console.log(newNode);
      this.tail.next = newNode;
      this.tail = newNode;
      this.length++;
      return this;
    }
    prepend(value) {
      const newNode = {
        value: value,
        next: null,
      };
      newNode.next = this.head;
      this.head = newNode;
      this.length++;
      return this;
    }
    printList() {
      const array = [];
      let currentNode = this.head;
      while (currentNode !== null) {
        array.push(currentNode.value);
        currentNode = currentNode.next;
      }
      return console.log(array);
    }
    insert(index, value) {
      //Check for proper parameters;
      if (index >= this.length) {
        console.log("yes");
        return this.append(value);
      }
  
      const newNode = {
        value: value,
        next: null,
      };
      const leader = this.traverseToIndex(index - 1);
      const holdingPointer = leader.next;
      leader.next = newNode;
      newNode.next = holdingPointer;
      this.length++;
      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) {
      // Check Parameters
      const leader = this.traverseToIndex(index - 1);
      const unwantedNode = leader.next;
      leader.next = unwantedNode.next;
      this.length--;
      return this.printList();
    }
    reverse() {
      if (!this.head.next) {
        return this.head;
      }
      let first = this.head;
      let second = first.next;
      while (second) {
        const temp = second.next;
        second.next = first;
        first = second;
        second = temp;
      }
      this.head.next = null;
      this.head = first;
      return this.printList();
    }
  }
  
  let myLinkedList = new LinkedList(10);
  myLinkedList.append(5);
  myLinkedList.append(16);
  myLinkedList.prepend(1);
  myLinkedList.printList();
  myLinkedList.insert(2, 99);
  myLinkedList.insert(20, 88);
  myLinkedList.printList();
  myLinkedList.remove(2);
  myLinkedList.reverse();