* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
		
			
				
	
	
		
			165 lines
		
	
	
		
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			165 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| ---
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| id: 5a24c314108439a4d4036169
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| title: Pass Props to a Stateless Functional Component
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| challengeType: 6
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| forumTopicId: 301402
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| dashedName: pass-props-to-a-stateless-functional-component
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| ---
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| 
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| # --description--
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| 
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| The previous challenges covered a lot about creating and composing JSX elements, functional components, and ES6 style class components in React. With this foundation, it's time to look at another feature very common in React: **props**. In React, you can pass props, or properties, to child components. Say you have an `App` component which renders a child component called `Welcome` which is a stateless functional component. You can pass `Welcome` a `user` property by writing:
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| 
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| ```jsx
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| <App>
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|   <Welcome user='Mark' />
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| </App>
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| ```
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| 
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| You use **custom HTML attributes** created by you and supported by React to be passed to the component. In this case, the created property `user` is passed to the component `Welcome`. Since `Welcome` is a stateless functional component, it has access to this value like so:
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| 
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| ```jsx
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| const Welcome = (props) => <h1>Hello, {props.user}!</h1>
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| ```
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| 
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| It is standard to call this value `props` and when dealing with stateless functional components, you basically consider it as an argument to a function which returns JSX. You can access the value of the argument in the function body. With class components, you will see this is a little different.
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| 
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| # --instructions--
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| 
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| There are `Calendar` and `CurrentDate` components in the code editor. When rendering `CurrentDate` from the `Calendar` component, pass in a property of `date` assigned to the current date from JavaScript's `Date` object. Then access this `prop` in the `CurrentDate` component, showing its value within the `p` tags. Note that for `prop` values to be evaluated as JavaScript, they must be enclosed in curly brackets, for instance `date={Date()}`.
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| 
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| # --hints--
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| 
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| The `Calendar` component should return a single `div` element.
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| 
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| ```js
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| assert(
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|   (function () {
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|     const mockedComponent = Enzyme.mount(React.createElement(Calendar));
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|     return mockedComponent.children().type() === 'div';
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|   })()
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| );
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| ```
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| 
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| The second child of the `Calendar` component should be the `CurrentDate` component.
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| 
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| ```js
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| assert(
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|   (function () {
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|     const mockedComponent = Enzyme.mount(React.createElement(Calendar));
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|     return mockedComponent.children().childAt(1).name() === 'CurrentDate';
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|   })()
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| );
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| ```
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| 
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| The `CurrentDate` component should have a prop called `date`.
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| 
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| ```js
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| assert(
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|   (function () {
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|     const mockedComponent = Enzyme.mount(React.createElement(Calendar));
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|     return mockedComponent.children().childAt(1).props().date;
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|   })()
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| );
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| ```
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| 
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| The `date` prop of the `CurrentDate` should contain a string of text.
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| 
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| ```js
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| assert(
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|   (function () {
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|     const mockedComponent = Enzyme.mount(React.createElement(Calendar));
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|     const prop = mockedComponent.children().childAt(1).props().date;
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|     return typeof prop === 'string' && prop.length > 0;
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|   })()
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| );
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| ```
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| 
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| The `date` prop should be generated by calling `Date()`
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| 
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| ```js
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| assert(/<CurrentDatedate={Date\(\)}\/>/.test(__helpers.removeWhiteSpace(code)));
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| ```
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| 
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| The `CurrentDate` component should render the value from the `date` prop in the `p` tag.
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| 
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| ```js
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| let date = 'dummy date';
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| assert(
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|   (function () {
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|     const mockedComponent = Enzyme.mount(
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|       React.createElement(CurrentDate, { date })
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|     );
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|     return mockedComponent.find('p').html().includes(date);
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|   })()
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| );
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| ```
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| 
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| # --seed--
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| 
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| ## --after-user-code--
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| 
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| ```jsx
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| ReactDOM.render(<Calendar />, document.getElementById('root'))
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| ```
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| 
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| ## --seed-contents--
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| 
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| ```jsx
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| const CurrentDate = (props) => {
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|   return (
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|     <div>
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|       { /* Change code below this line */ }
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|       <p>The current date is: </p>
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|       { /* Change code above this line */ }
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|     </div>
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|   );
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| };
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| 
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| class Calendar 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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|     return (
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|       <div>
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|         <h3>What date is it?</h3>
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|         { /* Change code below this line */ }
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|         <CurrentDate />
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|         { /* Change code above this line */ }
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|       </div>
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|     );
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|   }
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| };
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| ```
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| 
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| # --solutions--
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| 
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| ```jsx
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| const CurrentDate = (props) => {
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|   return (
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|     <div>
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|       { /* Change code below this line */ }
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|       <p>The current date is: {props.date}</p>
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|       { /* Change code above this line */ }
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|     </div>
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|   );
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| };
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| 
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| class Calendar 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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|     return (
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|       <div>
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|         <h3>What date is it?</h3>
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|         { /* Change code below this line */ }
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|         <CurrentDate date={Date()} />
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|         { /* Change code above this line */ }
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|       </div>
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|     );
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|   }
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| };
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| ```
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