Had a problem in chapter 3.

[jdavidmcgee]

Dave,

Love your stuff! You are the best. Thank you all all you're doing to help us new and inspiring developers.

In chapter three (I believe) I ran into a problem where the code added the 100 posts twice...creating a 200 post rendering and some weird behaviors for clicking on the emojis. When I added a new post it would place the new post right after the first post...not before.

I don't know the reason for this entirely...since I'm still new to the react and redux world but I hung with it for a while and eventually, in the postsSlice.js file (somewhere around line 88), I changed the code from:

'state.posts = state.posts.concat(loadedPosts);'

to

'state.posts = loadedPosts;'

With this change the rendering of all the posts twice stopped. With this change I also noticed that when I created a new post it was placed on the top. So I'm wondering if maybe between when you released the video tutorials and now (a couple of years later) maybe react, reduce, thunk or axios or something else has updated that created this twice rendering and making a 200 entry list of posts problem.

I wanted you to know what I encountered and how it was maybe fixed(???? time will tell as I do more work).

Wishing you all the best.

my email is jdavidmcgee@mac.com if you want to share any further insights...I am a new developer in training and your stuff is really really good!

All the best,

David

[quantuan125]

I'm encountering the issue and apparently the issue lies in the fact that "fetchPosts" function is being called twice at render.

I asked Claude and it points out to the issue being in React Strictmode but there seems to be no solution around this. I suspect something is has changed with the "createAsyncThunk" as well.

#EDIT:

I have found two solutions for this.

##SOLUTION 1: Remove Strictmode.

In index.js, remove the React.Strictmode components:
""
store.dispatch(fetchUsers())

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(



<Route path='/*' element={}/>

);
""

##SOLUTION 2: Use "useRef" from React inside the "useEffect" hook for calling fetchPosts
""
useEffect(() => {
if (effectRan.current === false) {
if (postsStatus === 'idle') {
console.log('Dispatching fetchPosts')
dispatch(fetchPosts())
}
return () => {
effectRan.current = true
}
}
}, [postsStatus, dispatch])

console.log('PostsList rendered, status:', postsStatus)
""

[Lam-Big-Water]

// original
state.posts = state.posts.concat(loadedPosts)

// changed
state.posts = loadedPosts

render twice problem can resolve