# Creating data - React 18 Tutorial

**URL:** <https://forum.codewithmosh.com/t/creating-data-react-18-tutorial/30384>\
**Category:** React\
**Created:** [December 7, 2024, 1:22pm UTC](https://forum.codewithmosh.com/t/creating-data-react-18-tutorial/30384 "2024-12-07T13:22:35Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![swaka](https://avatars.discourse-cdn.com/v4/letter/s/da6949/32.png) [@swaka](https://forum.codewithmosh.com/u/swaka)\
**Post date:** [December 7, 2024, 1:22pm UTC](https://forum.codewithmosh.com/t/creating-data-react-18-tutorial/30384/1 "2024-12-07T13:22:35Z")

</div>

In the Creating Data video of Connecting to the Backend, Mosh does this:

```
const addUser = () => {
const originalUsers = [...users];
const newUser = { id: 0, name: "Mosh" };
setUsers([newUser, ...users]);`

axios
  .post("https://jsonplaceholder.typicode.com/users", newUser)
  .then(({ data: savedUser }) => setUsers([savedUser, ...users]))
  .catch((err) => {
    setError(err.message);
    setUsers(originalUsers);
  });
};

```

Why is the new user being added to the state variable twice?  
`setUsers([newUser, ...users]);`  
`setUsers([savedUser, ...users])`

This doesn’t actually add it twice in practice but I think that is only because React updates state variables asynchronously.

Is this a mistake or am I missing something?

---

<div class="post-metadata">

**Author:** ![URMine4Ever](https://avatars.discourse-cdn.com/v4/letter/u/a87d85/32.png) [@URMine4Ever](https://forum.codewithmosh.com/u/URMine4Ever)\
**Post date:** [December 12, 2024, 6:45pm UTC](https://forum.codewithmosh.com/t/creating-data-react-18-tutorial/30384/2 "2024-12-12T18:45:53Z")

</div>

they are added twice but they have different id. Mosh used optimistic approach so `setUsers([newUser, ...users]);` is before the post method. while `setUsers([savedUser, ...users])` is after post without error. Mosh mention that when you get back from server, it would have a unique id but its fake backend, it would be the same adding it at the end.

Try the test I did. put `{user.id}` next to the `{user.name}` in the `<li>`. In Network tab, change no throttling to 3G or slower. Then press the Add button. You will see that the id was first 0 then it changes into 11.