7.3 KiB
7.3 KiB
id, title, challengeType, isRequired, forumTopicId, localeTitle
id | title | challengeType | isRequired | forumTopicId | localeTitle |
---|---|---|---|---|---|
5a24c314108439a4d4036144 | Use Provider to Connect Redux to React | 6 | false | 301435 | Использовать Провайдер для подключения Redux к действию |
Description
react-redux
для выполнения этих задач. React Redux предоставляет небольшой API с двумя ключевыми функциями: Provider
и connect
. Другая проблема connect
. Provider
- это оболочка из React Redux, которая обертывает ваше приложение React. Затем этот обертку позволяет вам получить доступ к функциям store
Redux и функции dispatch
во всем дереве компонентов. Provider
берет два реквизита, магазин Redux и дочерние компоненты вашего приложения. Определение Provider
для компонента приложения может выглядеть так: <Магазин-провайдер = {store}>
<Приложение />
</ Provider>
Instructions
DisplayMessages
component. The only new piece is the AppWrapper
component at the bottom. Use this top level component to render the Provider
from ReactRedux
, and pass the Redux store as a prop. Then render the DisplayMessages
component as a child. Once you are finished, you should see your React component rendered to the page.
Note: React Redux is available as a global variable here, so you can access the Provider with dot notation. The code in the editor takes advantage of this and sets it to a constant Provider
for you to use in the AppWrapper
render method.
Tests
tests:
- text: The <code>AppWrapper</code> should render.
testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); return mockedComponent.find('AppWrapper').length === 1; })());
- text: The <code>Provider</code> wrapper component should have a prop of <code>store</code> passed to it, equal to the Redux store.
testString: getUserInput => assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); return getUserInput('index').replace(/\s/g,'').includes('<Providerstore={store}>'); })());
- text: <code>DisplayMessages</code> should render as a child of <code>AppWrapper</code>.
testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); return mockedComponent.find('AppWrapper').find('DisplayMessages').length === 1; })());
- text: The <code>DisplayMessages</code> component should render an h2, input, button, and <code>ul</code> element.
testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(AppWrapper)); return mockedComponent.find('div').length === 1 && mockedComponent.find('h2').length === 1 && mockedComponent.find('button').length === 1 && mockedComponent.find('ul').length === 1; })());
Challenge Seed
// Redux Code:
const ADD = 'ADD';
const addMessage = (message) => {
return {
type: ADD,
message
}
};
const messageReducer = (state = [], action) => {
switch (action.type) {
case ADD:
return [
...state,
action.message
];
default:
return state;
}
};
const store = Redux.createStore(messageReducer);
// React Code:
class DisplayMessages 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>
);
}
};
const Provider = ReactRedux.Provider;
class AppWrapper extends React.Component {
// render the Provider here
// change code above this line
};
After Tests
ReactDOM.render(<AppWrapper />, document.getElementById('root'))
Solution
// Redux Code:
const ADD = 'ADD';
const addMessage = (message) => {
return {
type: ADD,
message
}
};
const messageReducer = (state = [], action) => {
switch (action.type) {
case ADD:
return [
...state,
action.message
];
default:
return state;
}
};
const store = Redux.createStore(messageReducer);
// React Code:
class DisplayMessages 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>
);
}
};
const Provider = ReactRedux.Provider;
class AppWrapper extends React.Component {
// change code below this line
render() {
return (
<Provider store = {store}>
<DisplayMessages/>
</Provider>
);
}
// change code above this line
};