Minor RTK Mutation Query Function Documentation Fix

[weixin-tan]

Fix mutation function usage, according to part 7 an .unwrap() call is needed.

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name: 📝 Documentation Fix
about: Fixing a problem in an existing docs page

Checklist

• Is there an existing issue for this PR?
  • Minor RTK mutation function call fix #4577
• Have the files been linted and formatted?

What docs page needs to be fixed?

• Section: Redux Essentials
• Page: Part 8 RTK Query Advanced Patterns

What is the problem?

Seems like a minor typo/missing function call in the usage of mutation function. In part 7, it is stated that the .unwrap() function needs to be called for the RTK mutation query.

As with the thunk dispatch, we call addNewPost with the initial post object. This returns a special Promise with a .unwrap() method, and we can await addNewPost().unwrap() to handle any potential errors with a standard try/catch block.

Whereas in part 8 code snippet for Editing Post, the .unwrap() call is missing for a very similar mutation function.

  const [updatePost, { isLoading }] = useEditPostMutation()

  /* code omitted */

  const onSavePostClicked = async () => {
    if (title && content) {
      await updatePost({ id: postId, title, content }) // <- this should have a .unwrap() ?
      history.push(`/posts/${postId}`)
    }
  }

What changes does this PR make to fix the problem?

Add .unwrap() to the code snippet

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[markerikson]

Strictly speaking, the .unwrap() isn't needed here. Dispatching the mutation trigger will return a promise either way - it's just that it always resolves. .unwrap() is only needed if you want to convert that back into a potential thrown error:

• https://redux-toolkit.js.org/api/createAsyncThunk#unwrapping-result-actions