Length of Linked list in javascript

There are two ways to find length of linked list —

1. Simple - Looping through complete linked list till next=null
2. Recursively incrementing the length till reached last

In this article- i am going to explain both ways.

Simple- using loop

class Node {
    constructor(value) {
        this.value = value;
        this.next = null;
    }
}
class LinkedList {
   add(value) {
        let root = this.root;
        let node = new Node(value);
        if (root == null) {
            this.root = node;
        } else {
            while (root.next != null) {
                root = root.next;
            }
            root.next = node;
        }
    }
    length() {
        let root = this.root;
        let length = 0;
        while (root != null) {
            root = root.next;
            ++length;
        }
        return length;
    }
}
const list = new LinkedList();
list.add(5);
list.add(51);
list.add(52);
console.log("length", list.length());

Recursively

class Node {
    constructor(value) {
        this.value = value;
        this.next = null;
    }
}
class LinkedList {
   add(value) {
        let root = this.root;
        let node = new Node(value);
        if (root == null) {
            this.root = node;
        }
        else {
            while (root.next != null) {
                root = root.next;
            }
            root.next = node;
        }
    }
    lengthUsingRecursion() {
        const length = (root) => {
            if (root == null) {
                return 0;
            }
            return 1 + length(root.next);
        }
        return length(this.root);
    }
}
const list = new LinkedList();
list.add(5);
list.add(51);
list.add(52);
console.log("length by recursion", list.lengthUsingRecursion());