React - 內容直到刷新後才會載入 - 狀態管理問題

Question

資料在我刷新頁面之前不會載入。我認為問題是狀態管理，但似乎無法使其工作。非常感謝任何幫助！

當使用者註冊帳戶時，他們登入會話中，所有使用者的貼文應該被渲染出來。然而，在我的情況下，直到我刷新頁面才會渲染出來。

client/src/context/ContentContext.js

import { createContext, useContext, useEffect, useState } from "react";
import { ErrorContext } from "./ErrorContext";

const ContentContext = createContext({});
const ContentProvider = ({children}) => {
    const { setErrors } = useContext(ErrorContext);
    const [contents, setContents] = useState([]);

    useEffect(() => {
        fetch('/posts')
        .then(resp => {
            if (resp.ok) {
                resp.json().then(data => {
                    setContents(data);
                });
            }
        })
        .catch(errors => {
            setErrors(errors);
        });
    }, [setErrors])

    const addPost = (newPost) => {
        setContents([...contents, newPost]);
    }

    const editPost = (newPost) => {
        const updatedContentList = contents.map(post => {
            if (newPost.id === post.id) {
                return newPost
            } else {
                return post;
            }
        });
        setContents(updatedContentList);
    }

    const deletePost = (id) => {
        const updatedContentList = contents.filter(post => post.id !== id)
        setContents(updatedContentList);
    }

    return (
        <ContentContext.Provider value={{ contents, addPost, editPost, deletePost }}>{children}</ContentContext.Provider>
    )
}

export { ContentContext, ContentProvider }

client/src/posts/PostDetail.js

import { useContext, useEffect, useState } from "react";

function PostDetail () {
    const { setErrors } = useContext(ErrorContext);
    const { user } = useContext(UserContext);
    const { contents, deletePost } = useContext(ContentContext);
    const postId = parseInt(useParams().id);
    const post = contents.find(post => post.id === postId);

    useEffect(() => {
        fetch(`/posts/${post.id}/likes`)
           .then(resp => resp.json())
           .then(data => {
               setLiked(data.liked);
           })
           .catch(error => {
               setErrors(error)
           })
         }, [post.id, setErrors])
     }

export default PostDetail;

Answer 1

我認為應該沒問題：

import React, { useContext, useEffect, useState } from "react";
import { ErrorContext } from "./ErrorContext";
import { AuthContext } from "./AuthContext"; 

const ContentProvider = ({ children }) => {
  const { setErrors } = useContext(ErrorContext);
  const { isLoggedIn } = useContext(AuthContext); 
  const [contents, setContents] = useState([]);
  const [loading, setLoading] = useState(true); 

  useEffect(() => {
    if (isLoggedIn) {
      fetch('/posts')
        .then((resp) => {
          if (resp.ok) {
            resp.json().then((data) => {
              setContents(data);
              setLoading(false); 
            });
          } else {
            setLoading(false); 
            setErrors("Err");
          }
        })
        .catch((error) => {
          setLoading(false); 
          setErrors(error);
        });
    }
  }, [isLoggedIn, setErrors]);

  return (
    <ContentContext.Provider value={{ contents, setLoading }}>
      {loading ? <p>加载中...</p> : children}
    </ContentContext.Provider>
  );
};

export { ContentProvider };