6.0 KiB
6.0 KiB
id | title | challengeType | isRequired | videoUrl | localeTitle |
---|---|---|---|---|---|
5a24c314108439a4d4036148 | Connect Redux to the Messages App | 6 | false | 将Redux连接到消息应用程序 |
Description
connect
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Presentational
,这不是任意的。该术语通常是指未直接连接到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。 Instructions
Presentational
。创建一个名为Container
的常量中保存的新组件,该常量使用connect
将Presentational
组件连接到Redux。然后,在AppWrapper
,渲染React Redux Provider
组件。将Redux store
Provider
作为道具传递,并将Container
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。 Tests
tests:
- text: <code>AppWrapper</code>应该呈现给页面。
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.");'
- text: <code>Presentational</code>组件应呈现<code>h2</code> , <code>input</code> , <code>button</code>和<code>ul</code>元素。
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.");'
- text: <code>Presentational</code>组件应呈现<code>h2</code> , <code>input</code> , <code>button</code>和<code>ul</code>元素。
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.");'
- text: <code>Presentational</code>组件应该从Redux商店接收<code>messages</code>作为道具。
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.");'
- text: <code>Presentational</code>组件应该接收<code>submitMessage</code>操作创建者作为prop。
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.");'
Challenge Seed
// Redux:
const ADD = 'ADD';
const addMessage = (message) => {
return {
type: ADD,
message: message
}
};
const messageReducer = (state = [], action) => {
switch (action.type) {
case ADD:
return [
...state,
action.message
];
default:
return state;
}
};
const store = Redux.createStore(messageReducer);
// React:
class Presentational extends React.Component {
constructor(props) {
super(props);
this.state = {
input: ",
messages: []
}
this.handleChange = this.handleChange.bind(this);
this.submitMessage = this.submitMessage.bind(this);
}
handleChange(event) {
this.setState({
input: event.target.value
});
}
submitMessage() {
const currentMessage = this.state.input;
this.setState({
input: ",
messages: this.state.messages.concat(currentMessage)
});
}
render() {
return (
<div>
<h2>Type in a new Message:</h2>
<input
value={this.state.input}
onChange={this.handleChange}/><br/>
<button onClick={this.submitMessage}>Submit</button>
<ul>
{this.state.messages.map( (message, idx) => {
return (
<li key={idx}>{message}</li>
)
})
}
</ul>
</div>
);
}
};
// React-Redux:
const mapStateToProps = (state) => {
return { messages: state }
};
const mapDispatchToProps = (dispatch) => {
return {
submitNewMessage: (newMessage) => {
dispatch(addMessage(newMessage))
}
}
};
const Provider = ReactRedux.Provider;
const connect = ReactRedux.connect;
// define the Container component here:
class AppWrapper extends React.Component {
constructor(props) {
super(props);
}
render() {
// complete the return statement:
return (null);
}
};
After Test
console.info('after the test');
Solution
// solution required