LinkedList

// myLinkedList = {
//     head: {
//         value: 10,
//         next: {
//             value: 5,
//             next: {
//                 value: 16,
//                 next: null
//             }
//         }
//     }
// }

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++;
    }
    
    prepend(value) {
        const newNode = new Node(value);
        newNode.next = this.head;
        this.head = newNode;
        this.length++;
    }
    
    printList() {
        const array = [];
        let currentNode = this.head;
        while (currentNode !== null) {
            array.push(currentNode.value);
            currentNode = currentNode.next;
        }
        return array;
    }
    
    insert(index, value) {
        // check params
        if(index === 0) {
             return this.prepend(value);
        }
        if(index >=this.length) {
            return this.append(value);
        }
        
        const newNode = new Node(value);
        const leader = this.traverseToIndex(index - 1);
        const holdingPointer = leader.next;
        leader.next = newNode;
        newNode.next = holdingPointer;
        this.length++;
        return this.printList();
    }
    
    traverseToIndex(index) {
        // check params
        let counter = 0;
        let currentNode = this.head;
        while (counter !== index) {
            currentNode = currentNode.next;
            counter++;
        }
        return currentNode;
    }
}

const myLinkedList = new LinkedList(10);
myLinkedList.append(5);
myLinkedList.append(16);
myLinkedList.prepend(1);
myLinkedList.insert(200, 99);
myLinkedList.insert(2, 201);
myLinkedList.insert(20, 88);
myLinkedList.printList();