IsPalindrome JavaScript SinglyLinkedList

PalindromeSingleLinkedList.js

Node = function(char){
  this.char = char;
};
Node.prototype = {
	createNext: function(char){
		this.next = new Node(char);
		return this.next;
	}

}

var asLinkedList = function(subject){
	var head = new Node(subject[0]);
	var current = head;
	var i = 1;
	while(i < subject.length){
		current = current.createNext(subject[i++]);
	}
	return head;
}

var reverseLink = function(node){
	var previous = null;
	while (true){
		next = node.next;
		node.next = previous;
		if (!next) return node;
		previous = node;
		node = next;
	}
}

var mid = function(head){
	var mid = head;
	var current = head;
	var count = 0;
	while(current.next != null && current.next.next != null){
		count++;
		current = current.next.next;
		mid = mid.next;
	}
	if ((count % 2) == 0)
		mid = mid.next;
	return mid;
}

var isPalindrome = function(head) {
	tail = reverseLink(mid(head))

	while (tail.char == head.char){
		if (tail.next  == null|| head.next == null){
			return true;
		}
		tail = tail.next;
		head = head.next;
	}

	return tail;
}

console.debug(isPalindrome(asLinkedList("aaa")));
console.debug(isPalindrome(asLinkedList("abccba")));
console.debug(isPalindrome(asLinkedList("lonnol")));
console.debug(isPalindrome(asLinkedList("bob")));
console.debug(isPalindrome(asLinkedList("1001")));

console.debug(isPalindrome(asLinkedList("Igor")));