Linked Lists

class Node {
    constructor(value) {
        this.value = value;
        this.next = null;
    }
}

class LinkedList {
      constructor(value) {
        this.head = new Node(value);
        this.tail = this.head;
        this.length = 1;
    }
    
    append(value){
        const newNode = new Node(value);
        
        this.tail.next = newNode;
        this.tail = newNode;
        this.length++;
        
        return this;
    }
    
    prepend(value){
        const newNode = new Node(value);
        
        this.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 array;
    }
    
    insert(index, value){
        if (index >= this.length) {
            this.append(value);
            return this.printList();
        }
        
        if (index === 0) {
           this.prepend(value);
           return this.printList();
            
        }

        const preNode = this._traverseToIndex(index - 1);
        const postNode = currentNode.next;
        const newNode = new Node(value);
        
        preNode.next = newNode;
        newNode.next = postNode;
        this.lenght++;
        
        return this.printList();
    }
    
    remove(index){
        const preNode = this._traverseToIndex(index - 1);
        const postNode = preNode.next.next;
        
        preNode.next = postNode;
        this.length--;
        return this.printList();
    }
    
     _traverseToIndex(index){
        let currentNode = this.head;
        let count = 0;
        
        while(count !== index) {
            currentNode = currentNode.next;
            count++;
        }
        return currentNode;
    }
}

const myLinkedList = new LinkedList(1);
myLinkedList.append(2);
myLinkedList.append(3);
myLinkedList.append(4);
myLinkedList.append(5);
myLinkedList.insert(2, 100);
myLinkedList.insert(4, 400);

console.log('myLinkedList:', myLinkedList.printList());