ES6 Linked List

es6_linked_list.js

class LinkedList {
    constructor() {
        this.head = null;
        this.tail = null;
    }

    addToHead(value) {
        let newNode = new Node(value, this.head, null);
        if (this.head) this.head.prev = newNode;
        else this.tail = newNode;
        this.head = newNode;
    }

    addToTail(value) {
        let newNode = new Node(value, null, this.tail)
        if (this.tail) this.tail.next = newNode;
        else this.head = newNode;
        this.tail = newNode;
    }
    
    removeHead() {
        if (!this.head) return null;
        let value = this.head.value;
        this.head = this.head.next;
        if(this.head) this.head.prev = null;
        else this.tail = null;
        return value;
    }

    removeTail() {
        if (!this.tail) return null;
        let value = this.tail.value;
        this.tail = this.tail.prev;
        if (this.tail) this.tail.prev = null;
        else this.head = null;
        return value;
    }

    search(searchValue) {
        let currentNode = this.head;
        while (currentNode) {
            if (currentNode.value === searchValue) {
                return currentNode.value;
            }
            currentNode = currentNode.next
        }
        return null;
    }
    
    indexOf(value) {
        let indexes = [];
        let i = 0;
        let currentNode = this.head;
        while (currentNode) {
            if(currentNode.value === value) indexes.push(i) 
            currentNode = currentNode.next
            i++
        }
        return indexes;
    }
};

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

var ll = new LinkedList();