Javascript 向兄弟姐妹传递道具时未定义
新的反应和尝试传递,道具组件与反应。但是在Track.js中接收Javascript 向兄弟姐妹传递道具时未定义,javascript,reactjs,ecmascript-6,jsx,Javascript,Reactjs,Ecmascript 6,Jsx,新的反应和尝试传递,道具组件与反应。但是在Track.js中接收{this.props.name}时,获取未定义的结果。和TypeError:无法读取未定义的属性“name” 在track.js呈现方法中尝试使用{this.props.track.name}时 它应该渲染这些轨迹: tracks: [{ name: 'Gold Slug', artist: 'DJ khaled',
{this.props.name}
时,获取未定义的
结果。和TypeError:无法读取未定义的属性“name”
在track.js呈现方法中尝试使用{this.props.track.name}
时
它应该渲染这些轨迹:
tracks: [{
name: 'Gold Slug',
artist: 'DJ khaled',
album: 'We da best',
id: '102 sample ID'
},
{
name: 'Slim shady',
artist: 'Eminem',
album: 'Marshal materials',
id: '103 sample ID'
}
或者这首歌:
searchResults: [{
name: 'You Mine',
artist: 'DJ Khaled',
album: 'I Changed a Lot',
id: '101 sample ID'
}],
背景信息:构建一个应用程序,用姓名、艺术家和专辑呈现歌曲曲目。还有一个包含搜索结果和播放列表的搜索。我正在使用6个组件:应用程序、播放列表、搜索栏、搜索结果、曲目和曲目列表
应用程序是一个容器。播放列表允许用户向其中添加曲目。SearchResults显示来自搜索栏的结果
在App.js中,我在构造函数方法中设置了searchResults的状态,并将其传递给组件
App.js:
import React from 'react';
import './App.css';
import SearchBar from '../SearchBar/SearchBar'
import SearchResults from "../SearchResults/SearchResults";
import Playlist from "../Playlist/Playlist";
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
searchResults: [{
name: 'You Mine',
artist: 'DJ Khaled',
album: 'I Changed a Lot',
id: '101 sample ID'
}],
tracks: [{
name: 'Gold Slug',
artist: 'DJ khaled',
album: 'We da best',
id: '102 sample ID'
},
{
name: 'Slim shady',
artist: 'Eminem',
album: 'Marshal materials',
id: '103 sample ID'
}
]
};
}
render() {
return (
<div>
<h1>Ja<span className="highlight">mmm</span>ing</h1>
<div className="App">
<SearchBar />
<div className="App-playlist">
<SearchResults searchResults={this.state.searchResults}/>
<Playlist />
</div>
</div>
</div>
);
}
}
export default App;
从“React”导入React;
导入“/App.css”;
从“../SearchBar/SearchBar”导入搜索栏
从“./SearchResults/SearchResults”导入搜索结果;
从“./Playlist/Playlist”导入播放列表;
类应用程序扩展了React.Component{
建造师(道具){
超级(道具);
此.state={
搜索结果:[{
名字:'你是我的',
艺人:“DJ Khaled”,
专辑:“我改变了很多”,
id:'101样本id'
}],
轨道:[{
名称:'金蛞蝓',
艺人:“DJ khaled”,
专辑:“我们是最棒的”,
id:'102样本id'
},
{
名称:'苗条树荫',
艺术家:“阿姆”,
专辑:“封送材料”,
id:'103样本id'
}
]
};
}
render(){
返回(
詹姆明
);
}
}
导出默认应用程序;
SearchResults接收并.map遍历数组,并将其设置为render方法中TrackList组件内的轨迹
SearchResults.js:
import React from 'react';
import './SearchResults.css'
import TrackList from "../TrackList/TrackList";
import Track from "../Track/Track";
class SearchResults extends React.Component {
render() {
return (
//Adds a map method that renders a set of Track components on the tracks attribute.
<div className="SearchResults">
<h2>Results</h2>
<TrackList tracks={this.props.searchResults.map(track => {
return <Track key={track.id} /> }
)} />
</div>
)
}
}
export default SearchResults;
从“React”导入React;
导入“./SearchResults.css”
从“./TrackList/TrackList”导入轨迹列表;
从“./Track/Track”导入曲目;
类SearchResults扩展了React.Component{
render(){
返回(
//添加在“轨迹”属性上渲染一组轨迹组件的贴图方法。
结果
{
返回}
)} />
)
}
}
导出默认搜索结果;
TrackList.js呈现一组轨迹组件:
import React from 'react';
import './TrackList.css'
import Track from '../Track/Track'
class TrackList extends React.Component {
render() {
return (
<div className="TrackList">
<Track />
<Track />
<Track />
<Track />
</div>
)
}
}
export default TrackList;
从“React”导入React;
导入“./TrackList.css”
从“../Track/Track”导入轨迹
类TrackList扩展了React.Component{
render(){
返回(
)
}
}
导出默认轨迹列表;
Track.js渲染轨迹:
import React from 'react';
import './Track.css'
class Track extends React.Component {
renderAction() {
if (this.props.isRemoval == true) {
return <h1>-</h1>;
} else {
return <h1>+</h1>;
}
}
//TODO: Fix rendering method on this.props.track.name
render() {
return (
<div className="Track">
<div className="Track-information">
<h3>{this.props.name}</h3>
<p>{`${this.props.artist} | ${this.props.album}`}</p>
</div>
<a className="Track-action" isRemoval={true}></a>
</div>
)
}
}
export default Track;
从“React”导入React;
导入“./Track.css”
类跟踪扩展了React.Component{
渲染(){
if(this.props.isRemoval==true){
返回-;
}否则{
返回+;
}
}
//TODO:修复此.props.track.name上的渲染方法
render(){
返回(
{this.props.name}
{`${this.props.artist}{this.props.album}}
)
}
}
导出默认轨迹;
这里的问题是,您实际上没有将数据向下传递到磁道
组件
class SearchResults extends React.Component {
render() {
return (
//Adds a map method that renders a set of Track components on the tracks attribute.
<div className="SearchResults">
<h2>Results</h2>
<TrackList tracks={this.props.searchResults.map(track => {
return <Track key={track.id} /> }
)} />
</div>
)
}
}
现在,在
Track
组件中,您可以访问this.props.Track.which
您没有向
组件传递任何道具
class SearchResults extends React.Component {
render() {
return (
//Adds a map method that renders a set of Track components on the tracks attribute.
<div className="SearchResults">
<h2>Results</h2>
<TrackList tracks={this.props.searchResults.map(track => {
return <Track key={track.id} track={track} /> }
)} />
</div>
)
}
}