162 lines
6.0 KiB
Markdown
162 lines
6.0 KiB
Markdown
---
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id: 5a24c314108439a4d4036148
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title: Connect Redux to the Messages App
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challengeType: 6
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isRequired: false
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videoUrl: ''
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localeTitle: 将Redux连接到消息应用程序
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---
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## Description
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<section id="description">现在您已了解如何使用<code>connect</code>将React连接到Redux，您可以将您学到的知识应用于处理消息的React组件。在上一课中，您连接到Redux的组件名为<code>Presentational</code> ，这不是任意的。该术语<i>通常</i>是指未直接连接到Redux的React组件。他们只负责UI的呈现，并根据他们收到的道具来执行此操作。相比之下，容器组件连接到Redux。这些通常负责将操作分派给商店，并且经常将商店状态作为道具传递给子组件。 </section>
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## Instructions
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<section id="instructions">到目前为止，代码编辑器包含了您在本节中编写的所有代码。唯一的变化是React组件被重命名为<code>Presentational</code> 。创建一个名为<code>Container</code>的常量中保存的新组件，该常量使用<code>connect</code>将<code>Presentational</code>组件连接到Redux。然后，在<code>AppWrapper</code> ，渲染React Redux <code>Provider</code>组件。将Redux <code>store</code> <code>Provider</code>作为道具传递，并将<code>Container</code>作为子项呈现。设置完所有内容后，您将再次看到应用程序呈现给页面的消息。 </section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>AppWrapper</code>应该呈现给页面。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); return mockedComponent.find("AppWrapper").length === 1; })(), "The <code>AppWrapper</code> should render to the page.");'
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- text: <code>Presentational</code>组件应呈现<code>h2</code> ， <code>input</code> ， <code>button</code>和<code>ul</code>元素。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); return mockedComponent.find("Presentational").length === 1; })(), "The <code>Presentational</code> component should render an <code>h2</code>, <code>input</code>, <code>button</code>, and <code>ul</code> elements.");'
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- text: <code>Presentational</code>组件应呈现<code>h2</code> ， <code>input</code> ， <code>button</code>和<code>ul</code>元素。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); const PresentationalComponent = mockedComponent.find("Presentational"); return ( PresentationalComponent.find("div").length === 1 && PresentationalComponent.find("h2").length === 1 && PresentationalComponent.find("button").length === 1 && PresentationalComponent.find("ul").length === 1 ); })(), "The <code>Presentational</code> component should render an <code>h2</code>, <code>input</code>, <code>button</code>, and <code>ul</code> elements.");'
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- text: <code>Presentational</code>组件应该从Redux商店接收<code>messages</code>作为道具。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); const PresentationalComponent = mockedComponent.find("Presentational"); const props = PresentationalComponent.props(); return Array.isArray(props.messages); })(), "The <code>Presentational</code> component should receive <code>messages</code> from the Redux store as a prop.");'
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- text: <code>Presentational</code>组件应该接收<code>submitMessage</code>操作创建者作为prop。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); const PresentationalComponent = mockedComponent.find("Presentational"); const props = PresentationalComponent.props(); return typeof props.submitNewMessage === "function"; })(), "The <code>Presentational</code> component should receive the <code>submitMessage</code> action creator as a prop.");'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='jsx-seed'>
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```jsx
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// Redux:
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const ADD = 'ADD';
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const addMessage = (message) => {
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return {
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type: ADD,
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message: message
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}
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};
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const messageReducer = (state = [], action) => {
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switch (action.type) {
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case ADD:
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return [
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...state,
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action.message
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];
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default:
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return state;
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}
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};
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const store = Redux.createStore(messageReducer);
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// React:
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class Presentational extends React.Component {
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constructor(props) {
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super(props);
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this.state = {
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input: ",
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messages: []
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}
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this.handleChange = this.handleChange.bind(this);
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this.submitMessage = this.submitMessage.bind(this);
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}
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handleChange(event) {
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this.setState({
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input: event.target.value
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});
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}
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submitMessage() {
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const currentMessage = this.state.input;
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this.setState({
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input: ",
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messages: this.state.messages.concat(currentMessage)
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});
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}
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render() {
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return (
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<div>
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<h2>Type in a new Message:</h2>
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<input
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value={this.state.input}
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onChange={this.handleChange}/><br/>
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<button onClick={this.submitMessage}>Submit</button>
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<ul>
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{this.state.messages.map( (message, idx) => {
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return (
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<li key={idx}>{message}</li>
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)
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})
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}
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</ul>
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</div>
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);
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}
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};
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// React-Redux:
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const mapStateToProps = (state) => {
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return { messages: state }
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};
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const mapDispatchToProps = (dispatch) => {
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return {
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submitNewMessage: (newMessage) => {
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dispatch(addMessage(newMessage))
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}
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}
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};
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const Provider = ReactRedux.Provider;
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const connect = ReactRedux.connect;
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// define the Container component here:
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class AppWrapper extends React.Component {
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constructor(props) {
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super(props);
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}
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render() {
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// complete the return statement:
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return (null);
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}
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};
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```
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</div>
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### After Test
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<div id='jsx-teardown'>
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```js
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console.info('after the test');
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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