A list exercise from Eloquent JS

EJS Exercise - A list.js

function List (value, rest) {
  this.value = value;
  this.rest = rest || null;
}

function arrayToList (array) {
  if (!array) return null;
  let list = new List(array[0], null);
  let tmp = list;
  for (let i = 1, len = array.length; i < len; i++) {
    tmp.rest = new List(array[i], null);
    tmp = tmp.rest;
  }
  return list;
}

console.log(arrayToList([1, 2, 3]));

function listToArray (list) {
  let out = [];
  let tmp = list;
  while (tmp.rest !== null) {
    out.push(tmp.value);
    tmp = tmp.rest;
  }
  return out;
}

console.log('array:',[1, 2, 3, 4, 5], 
            'arrayToList([1, 2, 3, 4, 5]):', arrayToList([1, 2, 3, 4, 5]),
            'listToArray(arrayToList([1, 2, 3, 4, 5])):', listToArray(arrayToList([1, 2, 3, 4, 5])));