Javascript redux状态的更改不会导致组件的更改/componentDidUpdate未调用
我有一个post details组件,单击like按钮,redux状态会改变,redux状态如下 职位 ->postDetails 我正在更改postDetais对象的like属性和like数,单击like按钮,like属性将从false设置为true,反之亦然,like数将增加 但是,状态正在更改,但componentDidUpdate方法未触发 PostDetails.jsJavascript redux状态的更改不会导致组件的更改/componentDidUpdate未调用,javascript,reactjs,redux,react-redux,Javascript,Reactjs,Redux,React Redux,我有一个post details组件,单击like按钮,redux状态会改变,redux状态如下 职位 ->postDetails 我正在更改postDetais对象的like属性和like数,单击like按钮,like属性将从false设置为true,反之亦然,like数将增加 但是,状态正在更改,但componentDidUpdate方法未触发 PostDetails.js import React, { Component } from "react"; import { connect
import React, { Component } from "react";
import { connect } from "react-redux";
import {
getPostData,
likePost,
unlikePost
} from "../../store/actions/postsActions";
import { Icon, Tooltip } from "antd";
import { Link } from "react-router-dom";
export class PostDetails extends Component {
state = {
postData: this.props.postDetails
};
componentDidMount() {
this.props.getPostData(this.props.match.params.post_id);
}
componentDidUpdate(prevProps, prevState, snapshot) {
console.log(this.props.postDetails);
if (prevProps.postDetails !== this.props.postDetails) {
this.setState({
postData: this.props.postDetails
});
}
}
render() {
const { postData } = this.state;
const liked = postData.liked;
return (
<div className="postDetails">
{postData && (
<div className="postDetailsContainer">
<div className="postImage">
<img src={postData.imageUrl} alt={postData.caption} />
</div>
<div className="postContent">
<div className="postContent__header">
<Link
to={`/user/${postData.username}`}
className="postContent__headerContent"
>
<img
src={postData.profileUrl}
alt={postData.username}
className="postContent__profileImage"
/>
<p className="postContent__username">{postData.username}</p>
</Link>
</div>
<div className="postComments" />
<div className="postInfo">
<div className="postActions">
{liked ? (
<Tooltip title="Unlike post">
<Icon
type="heart"
className="likePost"
theme="filled"
style={{ color: "#d41c00" }}
onClick={() => this.props.unlikePost(postData.id)}
/>
</Tooltip>
) : (
<Tooltip title="Like post">
<Icon
type="heart"
className="likePost"
onClick={() => this.props.likePost(postData.id)}
/>
</Tooltip>
)}
<Tooltip title="Comment">
<Icon type="message" className="commentButton" />
</Tooltip>
</div>
<Tooltip title="Refresh comments">
<Icon type="reload" className="reloadComments" />
</Tooltip>
</div>
<div />
</div>
</div>
)}
</div>
);
}
}
const mapStateToProps = state => {
return {
postDetails: state.posts.postDetails
};
};
const mapDispatchToProps = dispatch => {
return {
getPostData: postId => dispatch(getPostData(postId)),
likePost: postId => dispatch(likePost(postId)),
unlikePost: postId => dispatch(unlikePost(postId))
};
};
export default connect(
mapStateToProps,
mapDispatchToProps
)(PostDetails);
postsActions.js
import Axios from "axios";
import moment from "moment";
import store from "../store";
export const createPost = postData => {
return (dispatch, getState) => {
dispatch({ type: "CREATING_POST" });
Axios.post("/api/post/new", {
imageUrl: postData.imageUrl,
caption: postData.caption
})
.then(res => {
dispatch({ type: "CREATED_POST" });
dispatch({ type: "ADD_POST", payload: res.data.post });
})
.catch(err => {
console.log(err);
});
};
};
export const fetchFeed = () => {
return (dispatch, getState) => {
Axios.get("/api/user/feed")
.then(res => {
var feed = res.data.feed;
const state = store.getState();
const likedPosts = state.user.userData.likedPosts;
for (var i = 0; i < feed.length; i++) {
for (var j = 0; j < feed.length - i - 1; j++) {
if (moment(feed[j + 1].createdAt).isAfter(feed[j].createdAt)) {
var temp = feed[j];
feed[j] = feed[j + 1];
feed[j + 1] = temp;
}
}
}
for (var i = 0; i < feed.length; i++) {
if (likedPosts.indexOf(feed[i]._id) > -1) {
feed[i]["liked"] = true;
} else {
feed[i]["liked"] = false;
}
}
console.log(feed);
dispatch({ type: "FETCH_FEED", payload: feed });
})
.catch(err => {
console.log(err);
});
};
};
export const likePost = postId => {
return (dispatch, getState) => {
Axios.put("/api/post/like", { postId: postId })
.then(res => {
const feed = store.getState().posts.feed;
feed.forEach(post => {
if (post._id === postId) {
post.liked = true;
}
});
dispatch({ type: "UPDATE_FEED", payload: feed });
dispatch({ type: "LIKED_POST", payload: res.data.postId });
})
.catch(err => {
console.log(err);
});
};
};
export const unlikePost = postId => {
return (dispatch, getState) => {
Axios.put("/api/post/unlike", { postId: postId })
.then(res => {
const feed = store.getState().posts.feed;
feed.forEach(post => {
if (post._id === postId) {
post.liked = false;
}
});
dispatch({ type: "UPDATE_FEED", payload: feed });
dispatch({ type: "UNLIKED_POST", payload: res.data.postId });
})
.catch(err => {
console.log(err);
});
};
};
export const getPostData = postId => {
return (dispatch, getState) => {
Axios.get(`/api/post/${postId}`)
.then(res => {
const likedPosts = store.getState().user.userData.likedPosts;
if (likedPosts.indexOf(postId) > -1) {
res.data.post["liked"] = true;
} else {
res.data.post["liked"] = false;
}
dispatch({ type: "GET_POST_DATA", payload: res.data.post });
})
.catch(err => {
console.log(err);
});
};
};
export const resetFeedUpdated = () => {
return (dispatch, getState) => {
dispatch({ type: "RESET_FEED_UPDATED" });
};
};
export const resetCreatedPost = () => {
return (dispatch, getState) => {
dispatch({ type: "RESET_CREATED_POST" });
};
};
从“Axios”导入Axios;
从“时刻”中导入时刻;
从“./store”导入存储;
export const createPost=postData=>{
返回(调度,获取状态)=>{
分派({type:“CREATING_POST”});
Axios.post(“/api/post/new”{
imageUrl:postData.imageUrl,
标题:postData.caption
})
。然后(res=>{
分派({type:“CREATED_POST”});
分派({type:“ADD_POST”,payload:res.data.POST});
})
.catch(错误=>{
控制台日志(err);
});
};
};
导出常量fetchFeed=()=>{
返回(调度,获取状态)=>{
get(“/api/user/feed”)
。然后(res=>{
var feed=res.data.feed;
const state=store.getState();
const likedPosts=state.user.userData.likedPosts;
对于(变量i=0;i-1){
feed[i][“喜欢”]=true;
}否则{
feed[i][“liked”]=false;
}
}
控制台日志(feed);
分派({type:“FETCH_FEED”,有效负载:FEED});
})
.catch(错误=>{
控制台日志(err);
});
};
};
导出常量likePost=postId=>{
返回(调度,获取状态)=>{
put(“/api/post/like”,{postId:postId})
。然后(res=>{
const feed=store.getState().posts.feed;
feed.forEach(post=>{
如果(post.\U id==postId){
post.like=true;
}
});
分派({type:“UPDATE_FEED”,payload:FEED});
分派({type:“LIKED_POST”,payload:res.data.postId});
})
.catch(错误=>{
控制台日志(err);
});
};
};
export const unlikePost=postId=>{
返回(调度,获取状态)=>{
put(“/api/post/inspect”,{postId:postId})
。然后(res=>{
const feed=store.getState().posts.feed;
feed.forEach(post=>{
如果(post.\U id==postId){
post.like=false;
}
});
分派({type:“UPDATE_FEED”,payload:FEED});
分派({type:“UNLIKED_POST”,有效负载:res.data.postId});
})
.catch(错误=>{
控制台日志(err);
});
};
};
export const getPostData=postId=>{
返回(调度,获取状态)=>{
get(`/api/post/${postId}`)
。然后(res=>{
const likedPosts=store.getState().user.userData.likedPosts;
如果(如posts.indexOf(posted)>-1){
res.data.post[“liked”]=true;
}否则{
res.data.post[“liked”]=false;
}
分派({type:“GET_POST_DATA”,有效负载:res.DATA.POST});
})
.catch(错误=>{
控制台日志(err);
});
};
};
导出常量resetFeedUpdated=()=>{
返回(调度,获取状态)=>{
分派({type:“RESET\u FEED\u UPDATED”});
};
};
导出常量resetCreatedPost=()=>{
返回(调度,获取状态)=>{
分派({type:“RESET\u CREATED\u POST”});
};
};
你的喜欢的帖子
和不喜欢的帖子
reducer案例不是纯粹的——它们正在变异状态中现有的postDetails
对象,并将其放回状态
,因此connect
在对postDetails
进行简单的等价比较时,正在优化而不是重新渲染从组件更新中的上一个和下一个道具。确保您正在为postDetails
创建一个全新的值,例如:
case "LIKED_POST":
const { postDetails } = state;
const newPostDetails = {
...postDetails,
liked: true,
likes: postDetails.likes + 1,
};
return {
...state,
postDetails: newPostDetails
};
您应该检查比较if(prevProps.postDetails!==this.props.postDetails)
是否命中。因为使用like函数只更改同一对象的属性,比较将失败,因为它仍然是postDetails
的同一对象引用。尝试在减速器中返回新对象:
case "LIKED_POST":
const { postDetails } = state;
postDetails.liked = true;
postDetails.likes += 1;
return {
...state,
postDetails: {
...postDetails
},
}
另外,如果您没有更改组件内部但在Redux存储中的对象的任何内容,为什么不直接使用组件属性呢?您可以删除state对象和组件diddupdate
。您还可以将其重构为功能组件
render() {
const { postDetails: postData } = this.props;
...
}
在使用Redux时,永远不要忘记这三个原则
- 真理的单一来源
- 国家只准备好了
- 还原程序必须是纯函数:还原程序接受以前的状态和某些操作,并对其进行修改并返回新状态。我们永远不应该改变国家。我们应该创建新对象并返回它们
您已经改变了reducer函数中的现有状态。这不会触发componentdidupdate,因为connect方法(它检查MapStateTops)认为没有任何更改(它检查引用,并且因为引用没有更改,所以不会调用组件)
您可以使用Object.assign或使用spread运算符,这有助于使减缩器返回新对象
更改喜欢的和未链接的函数以返回新对象,而不是改变现有对象
@azundo添加了实现所需的代码的方式。使用componentWillReceiveProps
intead of componentdiddupdate。网址-。它叫夏娃
render() {
const { postDetails: postData } = this.props;
...
}