I have some problems with "RTK Query"

Question

recently I've just started to read RTK Query's document in the redux.js.org and understood the doc's main project doesn't show the Posts in CodeSandbox and just [object Object] is obvioused except of the Posts list which should being loaded by the fake server included in the default project . secondly I couldn't managed the error in PostsList page (the Page which is included in the redux main project (simple social media)) .

features/posts/PostsList.js

 export const PostList = () => {
  const {
    data: posts = [],
    isSuccess,
    isLoading,
    isError,
    error,
  } = useGetPostsQuery()

  const orderedPosts = useMemo(() => {
    console.log(posts)
    const ordered = posts.posts.slice()
    ordered.sort((a, b) => b.date.localeCompare(a.date))
    return ordered
  }, [posts])

just got the [] as the posts value then this error appears "Cannot read properties of undefined (reading 'slice')"

and the whole the main project of redux is accessible right in this link rtk-query-basics

score 0 · Accepted Answer · answered Nov 02 '21 at 18:31

I believe the problem is in the following line:

const ordered = posts.posts.slice()

It is trying to access a posts property on the posts array, which returns undefined (most likely a typo). This would explain the error message, as undefined is not an array, and therefore does not have a slice method.

To fix the problem, amend the line to look like this:

const ordered = posts.slice()

I have some problems with "RTK Query"

1 Answers1