Accessing previous state within a useDispatch method

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  from this code

        import { View, Text } from 'react-native'
      
      import React from 'react'
      
      export default function App() {
        return (
          <View>
      
      <Text>Apps</Text>   
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  it's formatted to this

  import {
    View,
    Text
  } from 'react-native'
  
  import React from 'react'
  
  export default function App() {
    return ( <
      View >
  
      <
      Text > Apps < /Text>
  
  
      <
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• react-router-dom v6 params only numbers

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• How can I fixed my problem"FirebaseError: Firebase: Error (auth/invalid-api-key)."

  My environment variable is ok. No comas and name mistakes but they given me error like "FirebaseError: Firebase: Error (auth/invalid-api-key)". How can I fixed it. Please Help me...

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  console.log(firebaseConfig.storageBucket); ==========> undefined 
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• How to maintain global states created dynamically

  I am trying to Display list of items with then name and button to download its respective file Same list are available in different other screens. When I click on download

  1. State info sharing: It should start download and the state/progress of the download should be visible to same item available in different other screens.unique identifier is item id

  2. There can be parallel downloads

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• I'm trying to implement Infinite Scrolling in a React application using the IntersectionObserver API but i'm running into some issues

  I'm trying to implement infinite scrolling and it's supposed to work by getting data in pages from the API...and then using the IntersectionObserver API, checking for an intersection between the target Element and the viewport, and when there's one, request the next page and get the data and add it to the previous posts...While experimenting I was able to get it to sort of work but it sometimes keeps requesting for the same page and maybe goes into an infinite loop of requests. I was going to try to create a custom hook for it but because I was also using redux I did something like this:

  Here's the post component with the infinite scroll implementation:

  const Posts = ({ setCurrentId }) => {
  
  const classes = useStyles()
  const dispatch = useDispatch();
  
  const { posts } = useSelector((state) => state.posts);
  const { numberOfPages } = useSelector((state) => state.posts);
  const { currentPage } = useSelector((state) => state.posts);
  
  const [postsArr, setPostsArr] = useState([posts]);
  const [hasMore, setHasMore] = useState(false);
  const [pageNum, setPageNum] = useState(1);
  
  useEffect(() => {
      dispatch(getPosts((pageNum)))
      const newPostsArr = postsArr.concat(posts);
      setPostsArr(newPostsArr);
      setHasMore(numberOfPages > 0);
  }, [pageNum]);
  
  const { loading } = useSelector((state) => state.posts);
  
  const observer = useRef();
  const lastPostElementRef = useCallback((node) => {
      if (observer.current) observer.current.disconnect();
      observer.current = new IntersectionObserver((entries) => {
          if (entries[0].isIntersecting && hasMore) {
              setPageNum((prev) => prev + 1);
          }
          dispatch(getPosts(pageNum));
      });
      if (node) observer.current.observe(node);
      if (currentPage === numberOfPages) setHasMore(false);
  }, [hasMore]);
  
  if (!postsArr.length && !loading) return 'No posts found';
  else
      return (
          <Grid className={classes.container} container alignItems="stretch" spacing={3}>
              {postsArr[0].map((post, i) => (
                  (postsArr.length === i + 1) ? (
                      <Grid key={post._id} ref={lastPostElementRef} item xs={12} sm={6} md={6} lg={3} >
                          <Post post={post} setCurrentId={setCurrentId} />
                      </Grid>
                  ) : (
                      <Grid key={post._id} item xs={12} sm={6} md={6} lg={3}>
                          <Post post={post} setCurrentId={setCurrentId} />
                      </Grid>
                  )
              ))}
              <div>{loading && <CircularProgress />}</div>
              </Grid>
          )}
  export default Posts;
  

  Here's the action that gets dispatched:

  export const getPosts = (page) => async (dispatch) => {
  try {
      dispatch({ type: START_LOADING })
      const { data: { data, currentPage, numberOfPages } } = await api.fetchPosts(Number(page));
  
      dispatch({ type: FETCH_ALL, payload: { data, currentPage, numberOfPages } });
      dispatch({ type: END_LOADING })
  } catch (error) {
         console.log(error)
      }
  }
  

  And then the reducer:

  const postReducer = (state = [], action) => {
  switch (action.type) {
      case START_LOADING:
          return { ...state, loading: true };
      case END_LOADING:
          return { ...state, loading: false };
      case FETCH_ALL:
           return {
              ...state,
              posts: action.payload.data,
              currentPage: action.payload.currentPage,
              numberOfPages: action.payload.numberOfPages,
              // error: action.payload.error
          };
     default:
              return state;
      }
  }
  export default postReducer
  

  I don't think there's a need for this but here's the backend API controller function:

  const getPosts = async (req, res) => {
  const { page } = req.query;
  
  try {
      const LIMIT = 8;
      const startIndex = (Number(page) - 1) * LIMIT; //GET THE STARTING INDEX OF EVERY PAGE
      const total = await postMessage.countDocuments({});
  
      const posts = await postMessage.find().sort({ _id: -1 }).limit(LIMIT).skip(startIndex);
  
      res.status(200).json({ data: posts, currentPage: Number(page), numberOfPages: Math.ceil(total / LIMIT) });
  } catch (error) {
          res.status(404).json({ message: error.message });
      }
  }
  

  posts and postsArr returns undefined and the component returns this error:

  I hope this is detailed enough and I'd really appreciate a response on what I'm doing wrong or if there's a better way to accomplish my goal.
• unable to save to array react state from response from server

  Hi I'm trying to save my response.data to my array state of react but it never stores the correct array but when I do a temporary array it works.

  Any help would be appreciated, thanks!

   const [allstudentlist, setAllStudentlist] = useState([]);
  
  await Axios.post(currentUrl, params).then((res) => {
    // if res.data[0][]
    // if res data is there then ;
    if (res.data["error"]) {
      alert(res.data["error"]);
    } else {
      // alert("Register Successful");
      // console.log(res.data[0]);
      console.log(res.data);
      // works
      let temp = res.data;
      setAllStudentlist(...temp);
      // works
      console.log(temp);
      // returns an empty array
      console.log(allstudentlist);
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  });
  

  Reponse data

  reponse data

  I tried to test as well with a fake api but it looks like there is an issue with setting Arrays at react

  I tried to test with codeSandbox as well with a fake API and it does not work

  import "./styles.css";
  import React, { Component, useState, useEffect } from "react";
  
  import Axios from "axios";
  export default function App() {
    const [array2, setArray] = useState([]);
  
    function handleClick() {
      Axios.get("https://finalspaceapi.com/api/v0/character/?limit=2").then(
        function (response) {
          console.log(response.data);
          setArray(response.data);
          console.log(array2);
        }
      );
    }
    return (
      <div className="App">
        <h1>Hello CodeSandbox</h1>
        <h2>Start editing to see some magic happen!</h2>
        <button onClick={handleClick}></button>
      </div>
    );
  }
  
• How does React hook handle dependency lists when passing objects to child components?

  Parent component like this:

  function ParentComponent(){
    return (
      <ChildComponent data={{ x: 1, y: 2 }} />
    )
  }
  

  Child component like this:

  function ChildComponent({ data }){
    const [sum, set] = useState(0)
    
    useEffect(() => {
      set(data.x + data.y)
    }, [data])
  
    return (
      <div>{sum}</div>
    )
  }
  

  If it is like the above method, it will cause repeated rendering between subgroups, because the data is always changing. How should I deal with such a scenario?

  Of course I know it's possible to cache data in the parent component by const [data] = useState({ x: 1, y: 2 }), but I want to know if there is a better solution, if any object parameter is required useState to cache, is this implementation too complicated?

  In addition, it can also be stored in the child component through const dataRef = useRef(data), but if a value of data changes, it will not be recalculated.

  Other parameters such as functions and arrays are the same.

  What's wrong with my thinking?
• How do I call react function in js map?

  I have the below code, the problem is in the part where I am calling the RemoveProduct function in the map function:

  function AddOrder() {
      const d = new Date();
      let text = d.toString();
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      const [editUser] = useMutation(queries.EDIT_USER_CART);
      const [editProduct] = useMutation(queries.EDIT_PRODUCT);
  
      function RemoveProduct (x)  {
  
          let getProd = useQuery(queries.GET_PRODUCTS_BY_ID, {
            fetchPolicy: "network-only",
            variables: {
              _id : x._id
            },
          });
          console.log(getProd.quantity)
          console.log(x.quantity)
          let a = getProd.quantity - x.quantity
          console.log(a)
          editProduct({
            variables: {
              _id : x._id,
              quantity: a
            },
          });
          return null;
      }
  
      const { currentUser } = useContext(AuthContext);
  
      if (error) {
          return <h1> error</h1>;
      } else if (loading) {
          return <h1> loading</h1>;
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                  image: data.getUser.cart[i].image,
                  price: data.getUser.cart[i].price,
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          editUser({
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                  cart: [],
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  }
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  I get the following error when I run this code:

  Uncaught Error: Rendered more hooks than during the previous render.
  

  How can I fix this? I tried to create a separate component for RemoveProducts and call in this function but that did not work either.