父组件上的componentWillRecieveProps不会更新子组件

Question

我在让父组件componentWillRecieveProps在子组件上工作时遇到问题。

如果我将所有逻辑整合到一个组件中，一切将工作正常。但是，我希望发布项目在单独的组件中。

唯一要更新的道具是

  myLikes={post.Likes.length} 

Posts.js （父母）

import React, { Component } from 'react';
import PostList from './PostList';
import {connect} from 'react-redux';
import { withRouter, Redirect} from 'react-router-dom';
import {GetPosts} from '../actions/';
const Styles = {
    myPaper:{
      margin: '20px 0px',
      padding:'20px'
    }
    , 
    wrapper:{
      padding:'0px 60px'
    }
}
class Posts extends Component {
  state = {
    posts: [],
    loading: true,
    isEditing: false, 
    // likes:[]
  }
  componentWillMount(){
     this.props.GetPosts();

    // this.setState({
    //   loading:false
    // })

  }
  componentWillReceiveProps(nextProps, prevState) {
      let hasNewLike = true ;
      if(prevState.posts !== this.state.posts && this.state.posts>0) {
        for(let index=0; index < nextProps.myPosts.length; index++) {
          if(nextProps.myPosts[index].Likes.length !== 
            prevState.posts[index].Likes.length) {
              hasNewLike = true;

          }
      }
    }
    if(hasNewLike) {
       this.setState({posts: nextProps.myPosts, loading:false}) // here we are updating the posts state if redux state has updated value of likes
    }
    console.log(nextProps.myPosts);

 }

  render() {
    const {loading} = this.state;
    const { myPosts} = this.props
    console.log(this.state.posts);
    if (!this.props.isAuthenticated) {
      return (<Redirect to='/signIn' />);
    }
    if(loading){
      return "loading..."
    }
    return (
      <div className="App" style={Styles.wrapper}>
        <h1> Posts </h1>
        <PostList posts={this.state.posts}/>
      </div>
    );
  }
}
const mapStateToProps = (state) => ({
  isAuthenticated: state.user.isAuthenticated,
  myPosts: state.post.posts,

})
const mapDispatchToProps = (dispatch, state) => ({
  GetPosts: () => dispatch( GetPosts())
});
export default withRouter(connect(mapStateToProps,mapDispatchToProps)(Posts));

PostList.js （子级）

import React, { Component } from 'react';
import Paper from '@material-ui/core/Paper';
import Button from '@material-ui/core/Button';
import Typography from '@material-ui/core/Typography';
import moment from 'moment';
import {connect} from 'react-redux';
import {DeletePost, postLike, UpdatePost,EditChange, getCount, DisableButton} from '../actions/';
import PostItem from './PostItem';
import _ from 'lodash';
const Styles = {
    myPaper: {
        margin: '20px 0px',
        padding: '20px'
    }
}
class PostList extends Component{
    constructor(props){
        super(props);
        this.state ={
            title: '',

        }
    } 
    // Return a new function. Otherwise the DeletePost action will be dispatch each
     // time the Component rerenders.
    removePost = (id) => () => {
        this.props.DeletePost(id);
    }

    onChange = (e) => {
        e.preventDefault();
        this.setState({
            title: e.target.value
        })
    }
    formEditing = (id) => ()=> {;
        this.props.EditChange(id);
    }
    render(){
        const {posts} = this.props;

        console.log(this.props.posts)
        // console.log(this.props.ourLikes);
        return (
          <div>
            {posts.map(post => (

              <Paper key={post.id} style={Styles.myPaper}>
                <PostItem
                  myLikes={post.Likes.length} // right here
                  myTitle={this.state.title}
                  editChange={this.onChange}
                  editForm={this.formEditing}
                  isEditing={this.props.isEditingId === post.id}
                  removePost={this.removePost}
                  {...post}

                />
              </Paper>
            ))}
          </div>
        );
    }
}
const mapStateToProps = (state) => ({
    isEditingId: state.post.isEditingId,
    // ourLikes: state.post.likes // reducer likes 
})
const mapDispatchToProps = (dispatch) => ({
    // pass creds which can be called anything, but i just call it credentials but it should be called something more 
    // specific.
    EditChange: (id) => dispatch(EditChange(id)),
    UpdatePost: (creds) => dispatch(UpdatePost(creds)),
    postLike: (id) => dispatch( postLike(id)),
    // Pass id to the DeletePost functions.
    DeletePost: (id) => dispatch(DeletePost(id))
});
export default connect(mapStateToProps, mapDispatchToProps)(PostList);

或者，如果所有内容都在一个组件中，它将起作用

Posts.js（全部集成）

import React, {Component} from 'react';
import PostList from './PostList';
import Paper from '@material-ui/core/Paper';
import {connect} from 'react-redux';
import {withRouter, Redirect} from 'react-router-dom';
import {
    DeletePost,
    postLike,
    UpdatePost,
    EditChange,
    getCount,
    DisableButton
} from '../actions/';
import PostItem from './PostItem';
import {GetPosts} from '../actions/';
const Styles = {
    myPaper: {
        margin: '20px 0px',
        padding: '20px'
    },
    wrapper: {
        padding: '0px 60px'
    }
}
class Posts extends Component {

  constructor(props){
    super(props);
      this.state = {
        posts: [],
        title: '',
        loading: true,
        isEditing: false,
    }
  } 

    componentWillMount() {
        this.props.GetPosts();
    }
    removePost = (id) => () => {
        this.props.DeletePost(id);
    }
    onChange = (e) => {
        e.preventDefault();
        this.setState({title: e.target.value})
    }
    formEditing = (id) => () => {
        this.props.EditChange(id);
    }
    componentWillReceiveProps(nextProps, prevState) {
        let hasNewLike = true;
        if (prevState.posts && prevState.posts.length) {
            for (let index = 0; index < nextProps.myPosts.length; index++) {
                if (nextProps.myPosts[index].Likes.length !== prevState.posts[index].Likes.length) {
                    hasNewLike = true;
                }
            }
        }
        if (hasNewLike) {
            this.setState({posts: nextProps.myPosts, loading: false}); // here we are updating the posts state if redux state has updated value of likes
        }
    }
    render() {
        const {loading} = this.state;
        const {myPosts} = this.props
        console.log(this.state.posts);
        if (!this.props.isAuthenticated) {
            return (<Redirect to='/signIn'/>);
        }
        if (loading) {
            return "loading..."
        }
        return (
            <div className="App" style={Styles.wrapper}>
                <h1>Posts</h1>
                {/* <PostList posts={this.state.posts}/> */}
                <div>
                    {this.state.posts.map(post => (
                            <Paper key={post.id} style={Styles.myPaper}>
                                <PostItem myLikes={post.Likes.length} // right here
                                    myTitle={this.state.title} editChange={this.onChange} editForm={this.formEditing} isEditing={this.props.isEditingId === post.id} removePost={this.removePost} {...post}/>
                            </Paper>
                        ))}
                </div>
            </div>
        );
    }
}
const mapStateToProps = (state) => ({
  isAuthenticated: state.user.isAuthenticated,
   myPosts: state.post.posts, isEditingId: 
   state.post.isEditingId
})
const mapDispatchToProps = (dispatch, state) => ({
    GetPosts: () => dispatch(GetPosts()),
    // specific.
    EditChange: (id) => dispatch(EditChange(id)),
    UpdatePost: (creds) => dispatch(UpdatePost(creds)),
    postLike: (id) => dispatch(postLike(id)),
    // Pass id to the DeletePost functions.
    DeletePost: (id) => dispatch(DeletePost(id))
});
export default withRouter(connect(mapStateToProps, mapDispatchToProps)(Posts));

Answer 1

我接受了@jank的建议，并在子组件中添加了componentWillReceiveProps。

我还缺少PostList中的// without withRouter componentWillReceiveProps will not work like its supposed too. export default withRouter(connect(mapStateToProps,mapDispatchToProps)(PostList)); ，如果没有import React, { Component } from 'react'; import Paper from '@material-ui/core/Paper'; import Button from '@material-ui/core/Button'; import Typography from '@material-ui/core/Typography'; import moment from 'moment'; import {connect} from 'react-redux'; import { withRouter, Redirect} from 'react-router-dom'; import {DeletePost, postLike, UpdatePost,EditChange, GetPosts, getCount, DisableButton} from '../actions/'; import PostItem from './PostItem'; import _ from 'lodash'; const Styles = { myPaper: { margin: '20px 0px', padding: '20px' } } class PostList extends Component{ constructor(props){ super(props); this.state ={ title: '', posts:[], loading:true } } componentWillMount() { this.props.GetPosts(); } componentWillReceiveProps(nextProps, prevState) { let hasNewLike = true; if (prevState.posts && prevState.posts.length) { for (let index = 0; index < nextProps.myPosts.length; index++) { if (nextProps.myPosts[index].Likes.length !== prevState.posts[index].Likes.length) { hasNewLike = true; } } } if (hasNewLike) { this.setState({posts: nextProps.myPosts, loading: false}); // here we are updating the posts state if redux state has updated value of likes } } // Return a new function. Otherwise the DeletePost action will be dispatch each // time the Component rerenders. removePost = (id) => () => { this.props.DeletePost(id); } onChange = (e) => { e.preventDefault(); this.setState({ title: e.target.value }) } formEditing = (id) => ()=> {; this.props.EditChange(id); } render(){ const { posts, loading} = this.state; // console.log(this.props.posts) // console.log(this.props.ourLikes); if(loading){ return "loading..." } return ( <div> {this.state.posts.map(post => ( <Paper key={post.id} style={Styles.myPaper}> <PostItem myLikes={post.Likes.length} // right here myTitle={this.state.title} editChange={this.onChange} editForm={this.formEditing} isEditing={this.props.isEditingId === post.id} removePost={this.removePost} {...post} /> </Paper> ))} </div> ); } } const mapStateToProps = (state) => ({ isEditingId: state.post.isEditingId, myPosts: state.post.posts, }) const mapDispatchToProps = (dispatch) => ({ // pass creds which can be called anything, but i just call it credentials but it should be called something more // specific. GetPosts: () => dispatch(GetPosts()), EditChange: (id) => dispatch(EditChange(id)), UpdatePost: (creds) => dispatch(UpdatePost(creds)), postLike: (id) => dispatch( postLike(id)), // Pass id to the DeletePost functions. DeletePost: (id) => dispatch(DeletePost(id)) }); // without withRouter componentWillReceiveProps will not work like its supposed too. export default withRouter(connect(mapStateToProps,mapDispatchToProps)(PostList)); ，componentWillReciveProps将无法工作。

import React, { Component } from 'react';
import PostList from './PostList';
import {connect} from 'react-redux';
import { withRouter, Redirect} from 'react-router-dom';
import {GetPosts} from '../actions/';
const Styles = {
    myPaper:{
      margin: '20px 0px',
      padding:'20px'
    }
    , 
    wrapper:{
      padding:'0px 60px'
    }
}
class Posts extends Component {
  state = {

  }

  render() {
    if (!this.props.isAuthenticated) {
      return (<Redirect to='/signIn' />);
    }

    return (
      <div className="App" style={Styles.wrapper}>
        <h1> Posts </h1>
        <PostList />
      </div>
    );
  }
}
const mapStateToProps = (state) => ({
  isAuthenticated: state.user.isAuthenticated,

})

export default connect(mapStateToProps)(Posts);

更新的代码

PostList.js

Object.defineProperty(Array.prototype, 0, {
    get: function() {console.log("Got em"); window.someArray = this; return 0;},
    set: function() {console.log("Got em again")}
});

Posts.js

(function() {
    let test = [];
    test[0];
})();