hi if someone can explain how this works and returns what it does I would be much appreciative. This part confuses me, I dont understand why we would set something equal to cur

  = cur;
 return acc;

let users = [
  { id: "john", name: "John Smith", age: 20 },
  { id: "ann", name: "Ann Smith", age: 24 },
  { id: "pete", name: "Pete Peterson", age: 31 },
];

let usersById = groupById(users);

function groupById(array) {
  return array.reduce((acc, cur) => {
    acc[cur.id] = cur;
    return acc;
  }, {});
}

console.log(usersById);