Linked List

LinkedList.js

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

    addFirst(node) {
        if (this.head === null) {
            this.head = node
        } else {
            node.next = this.head
            this.head = node
        }
    }

    addLast(node) {
        if (this.head === null) {
            this.head = node
        } else {
            let current = this.head
            while (current.next !== null) {
                current = current.next
            }
            current.next = node
        }
    }

    indexOf(node) {
        let current = this.head
        let index = 0
        while (current !== null) {
            if (current === node) {
                return index
            }
            current = current.next
            index += 1
        }
        return -1
    }

    removeAt(index) {
        if (this.head === null) {
            return;
        }
        if (index === 0) {
            this.head = this.head.next;
            return;
        }
        let current = this.head;
        let previous;
        let i = 0;
        while (current !== null && i < index) {
            previous = current;
            current = current.next;
            i++;
        }
        if (current === null) {
            return;
        }
        previous.next = current.next;
    }
}

module.exports = LinkedList;

Node.js

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

module.exports = Node;