> For the complete documentation index, see [llms.txt](https://pburtchaell.gitbook.io/redux-promise-middleware/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://pburtchaell.gitbook.io/redux-promise-middleware/guides/optimistic-updates.md).

# Optimistic Updates

## What are optimistic updates?

> Optimistic \[updates to a UI] don't wait for an operation to finish to update to the final state. They immediately switch to the final state, showing fake data for the time while the real operation is still in-progress.
>
> * Igor Mandrigin, UX Planet

["Optimistic UI,"](https://uxplanet.org/optimistic-1000-34d9eefe4c05#.twmtjnmaw) a short article by UX Planet, is a great summary if you are unfamiliar with the practice. In short, it's the practice of updating the UI when a request is pending. This makes the experience more fluid for users.

Because promise middleware dispatches a pending action, it is easy to optimistically update the Redux store.

## Code

You may pass an optional `data` object. This is dispatched from the pending action and is useful for optimistic updates.

```javascript
const foo = data => ({
  type: 'FOO',
  payload: {
    promise: new Promise(),
    data: data
  }
});
```

Considering the action creator above, the pending action would be described as:

```javascript
// pending action
{
  type: 'FOO_PENDING',
  payload: data
}
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://pburtchaell.gitbook.io/redux-promise-middleware/guides/optimistic-updates.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.