Reverse a linked list in JavaScript and HTML.

reverseLinkedList.html

<pre id=o></pre>

<script>
class LinkedList {
  constructor(value, next) {
    this.value = value;
    this.next = next;
  }
}

const reverseList = head => {
  let curr = head;
  let temp = null;
  let prev = null;

  while (true) {
    temp = curr.next;
    curr.next = prev;
    prev = curr;
    if (!temp) break;
    curr = temp;
  }
  return curr;
};

const genLinkedList = arr => {
  let newNode;
  let head;
  let node;
  for (let i = 0; i < arr.length; i++) {
    newNode = new LinkedList(arr[i]);
    if (!head) {
      head = newNode;
      node = head;
    }
    else {
      node.next = newNode;
      node = node.next;
    }
  }
  return head;
};
  
const linkedListToArr = head => {
  let output = [];
  let node = head;
  while (node) {
    const { value, next } = node;
    output.push(value);
    node = next;
  }
  return output;
};

const linkedList = genLinkedList([1,2,3,4,5,6]);
const reversed = reverseList(linkedList);
o.innerHTML = linkedListToArr(reversed).join("\n");
</script>