[英]How should I fix eslint warning (React Hook useEffect has a missing dependency) and a loop caused by the warning?
In following codes, eslint will give a warning.在下面的代码中,eslint 会给出警告。
Line 24:6: React Hook useEffect has a missing dependency: 'fetchPosts'. Either include it or remove the dependency array react-hooks/exhaustive-deps
import { useState, useEffect } from 'react';
import { useLocation } from "react-router-dom";
import { Layout } from './Layout';
import { TwitterPost, reloadTwitterEmbedTemplate } from '../TwitterPost';
import '../../styles/pages/TimelinePage.css'
import axios from 'axios';
export const TimelinePage = () => {
const [posts, setPosts] = useState([]);
const [page, setPage] = useState(1);
const location = useLocation();
const fetchPosts = async () => {
const res = await axios.get('/api/posts', { params: { page: page } });
setPosts(posts.concat(res.data));
reloadTwitterEmbedTemplate();
setPage(page + 1);
};
useEffect(() => {
if (location.pathname !== '/') return;
fetchPosts();
}, [location]);
const postTemplates = posts.map((post: any) => {
if (post.media_name === 'twitter') return <TwitterPost mediaUserScreenName={post.media_user_screen_name} mediaPostId={post.media_post_id} />;
return null;
});
return(
<Layout body={
<div id="timeline">
<div>{postTemplates}</div>
<div className="show-more-box">
<button type="button" className="show-more-button" onClick={fetchPosts}>show more</button>
</div>
</div>
} />
);
};
I fixed the warning by adding fetchPosts
.我通过添加
fetchPosts
修复了警告。 Then I followed eslint instructions using useCallback
and adding variables used in fetchPosts
to deps.然后我按照 eslint 指令使用
useCallback
并将fetchPosts
中使用的变量添加到 deps。 This change causes a loop.此更改会导致循环。 How should I fix the loop and eslint warning?
我应该如何修复循环和 eslint 警告?
import { useState, useEffect, useCallback } from 'react';
import { useLocation } from "react-router-dom";
import { Layout } from './Layout';
import { TwitterPost, reloadTwitterEmbedTemplate } from '../TwitterPost';
import '../../styles/pages/TimelinePage.css'
import axios from 'axios';
export const TimelinePage = () => {
const [posts, setPosts] = useState([]);
const [page, setPage] = useState(1);
const location = useLocation();
const fetchPosts = useCallback(async () => {
const res = await axios.get('/api/posts', { params: { page: page } });
setPosts(posts.concat(res.data));
reloadTwitterEmbedTemplate();
setPage(page + 1);
}, [page, posts]);
useEffect(() => {
if (location.pathname !== '/') return;
fetchPosts();
}, [location, fetchPosts]);
const postTemplates = posts.map((post: any) => {
if (post.media_name === 'twitter') return <TwitterPost mediaUserScreenName={post.media_user_screen_name} mediaPostId={post.media_post_id} />;
return null;
});
return(
<Layout body={
<div id="timeline">
<div>{postTemplates}</div>
<div className="show-more-box">
<button type="button" className="show-more-button" onClick={fetchPosts}>show more</button>
</div>
</div>
} />
);
};
I highly recommend this article to really understand what's going on when you use the useEffect hook.我强烈推荐这篇文章来真正了解使用 useEffect 挂钩时发生了什么。 It talks, among other things, about your exact problem and ways to solve it.
除其他事项外,它还讨论了您的确切问题和解决方法。 That said, you should move the function inside the useEffect callback, something like:
也就是说,您应该在 useEffect 回调中移动 function ,例如:
export const TimelinePage = () => {
/* ... */
useEffect(() => {
if (location.pathname !== '/') return;
const fetchPosts = async () => {
const res = await axios.get('/api/posts', { params: { page: page } });
setPosts(posts.concat(res.data));
reloadTwitterEmbedTemplate();
setPage(page + 1);
}
fetchPosts();
}, [location]);
/* ... */
};
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