reverse list javascript

index.js

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

    insert(newNode) {
        let node = this.head;
        if (node==null) {
            this.head = newNode;
            return;
        }
        while (node.next) {
            node = node.next;
        }
        node.next = newNode;
    }

    print() {
        let node = this.head;
        process.stdout.write("HEAD->")
        while (node) {
            process.stdout.write(node.data + "->");
            node = node.next;
        }
        process.stdout.write("End\n");
    }

    reverse() {
        let node = this.head,
            prev = null,
            next;

        if (node && node.next) {
            while (node) {
                next = node.next;
                node.next = prev;
                prev = node;
                node = next;
            }

            this.head = prev;
        }

        return this;
    }
}

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

let myList = new List();

myList.insert(new Node(4));
myList.insert(new Node(3));
myList.insert(new Node(2));
myList.insert(new Node(1));
myList.insert(new Node(0));
myList.print();

myList.reverse().print();

if (node && node.next) { looks like a redundant check

Ok, let's try to remove the redundant check and execute

let myList = new List('c++');

myList.reverse().print();

Result

TypeError: Cannot create property 'next' on string 'c++'
    at List.reverse (/tmp/list.js:36:27)
    at Object.<anonymous> (/tmp/list.js:65:8)
    at Module._compile (node:internal/modules/cjs/loader:1254:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1308:10)
    at Module.load (node:internal/modules/cjs/loader:1117:32)
    at Module._load (node:internal/modules/cjs/loader:958:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:23:47

Please check

struct Node* reverseList(struct Node* head)
{
  Node* prev = nullptr;
  while (head != nullptr) {
    auto* tail = head->next;
    head->next = prev;
    prev = head;
    head = tail;
  }
  return prev;
}

It works fine with only while loop

Please check

struct Node* reverseList(struct Node* head)
{
  Node* prev = nullptr;
  while (head != nullptr) {
    auto* tail = head->next;
    head->next = prev;
    prev = head;
    head = tail;
  }
  return prev;
}

It works fine with only while loop

completely agree, It will work properly in C/C++. Using strictly typed language you have no chance to initialize Node with just a string. But JavaScript allows it