Nth item from the end of a list

nthFromEnd.js

"use strict";

let nthFromEnd = (startNode, n) => {
  let rabbit = startNode;
  let turtle = startNode;
  while(n--){
    rabbit=rabbit.nextNode;
  }
  while(rabbit){
    rabbit=rabbit.nextNode;
    turtle=turtle.nextNode
  }
  return turtle;
}

// create 10 node list
let nodes = [];
for (let i = 0; i < 10; i++){
  nodes.push({value:i, nextNode:null});
  if(i > 0){
    nodes[i-1].nextNode = nodes[i];
  }
}

console.log(nthFromEnd(nodes[0], 3).value); // 7