// Only change code below this line
function updateRecords(id, prop, value) {
  //check that id exists in collection
  if (collection[id] === undefined) {
    return console.log(`id: ${id} is not in collection`);
  }

  //set prop if it does not exists
  if (collection[id][prop] === undefined) {
    if (prop === "tracks") {
      if (collection[id][prop] === undefined) {
        collection[id][prop] = [];
      } else {
        collection[id][prop] = null;
      }
    }
  }

  //assign value to non tracks key
  if (prop != "tracks" && value != "") {
    collection[id][prop] = value;
  }

  if (prop === "tracks" && value != "") {
    collection[id][prop].push(value);
  }

  if (value === "") {
    delete collection[id][prop];
  }

  /*** */

  return collection;
}