* fix(curriculum): tests quotes * fix(curriculum): fill seed-teardown * fix(curriculum): fix tests and remove unneeded seed-teardown
		
			
				
	
	
		
			122 lines
		
	
	
		
			4.8 KiB
		
	
	
	
		
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			122 lines
		
	
	
		
			4.8 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| ---
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| id: 5a24c314108439a4d4036184
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| title: Render with an If-Else Condition
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| challengeType: 6
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| isRequired: false
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| ---
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| 
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| ## Description
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| <section id='description'>
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| Another application of using JavaScript to control your rendered view is to tie the elements that are rendered to a condition. When the condition is true, one view renders. When it's false, it's a different view. You can do this with a standard <code>if/else</code> statement in the <code>render()</code> method of a React component.
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| </section>
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| 
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| ## Instructions
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| <section id='instructions'>
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| MyComponent contains a <code>boolean</code> in its state which tracks whether you want to display some element in the UI or not. The <code>button</code> toggles the state of this value. Currently, it renders the same UI every time. Rewrite the <code>render()</code> method with an <code>if/else</code> statement so that if <code>display</code> is <code>true</code>, you return the current markup. Otherwise, return the markup without the <code>h1</code> element.
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| <strong>Note:</strong> You must write an <code>if/else</code> to pass the tests. Use of the ternary operator will not pass here.
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| </section>
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| 
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| ## Tests
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| <section id='tests'>
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| 
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| ```yml
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| tests:
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|   - text: <code>MyComponent</code> should exist and render.
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|     testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(MyComponent)); return mockedComponent.find('MyComponent').length === 1; })(), '<code>MyComponent</code> should exist and render.');
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|   - text: When <code>display</code> is set to <code>true</code>, a <code>div</code>, <code>button</code>, and <code>h1</code> should render.
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|     testString: 'async () => { const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 250)); const mockedComponent = Enzyme.mount(React.createElement(MyComponent)); const state_1 = () => { mockedComponent.setState({display: true}); return waitForIt(() => mockedComponent )}; const updated = await state_1(); assert(mockedComponent.find(''div'').length === 1 && mockedComponent.find(''div'').children().length === 2 && mockedComponent.find(''button'').length === 1 && mockedComponent.find(''h1'').length === 1, ''When <code>display</code> is set to <code>true</code>, a <code>div</code>, <code>button</code>, and <code>h1</code> should render.''); }; '
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|   - text: When <code>display</code> is set to <code>false</code>, only a <code>div</code> and <code>button</code> should render.
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|     testString: 'async () => { const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 250)); const mockedComponent = Enzyme.mount(React.createElement(MyComponent)); const state_1 = () => { mockedComponent.setState({display: false}); return waitForIt(() => mockedComponent )}; const updated = await state_1(); assert(mockedComponent.find(''div'').length === 1 && mockedComponent.find(''div'').children().length === 1 && mockedComponent.find(''button'').length === 1 && mockedComponent.find(''h1'').length === 0, ''When <code>display</code> is set to <code>false</code>, only a <code>div</code> and <code>button</code> should render.''); }; '
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|   - text: The render method should use an <code>if/else</code> statement to check the condition of <code>this.state.display</code>.
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|     testString: getUserInput => assert(getUserInput('index').includes('if') && getUserInput('index').includes('else'), 'The render method should use an <code>if/else</code> statement to check the condition of <code>this.state.display</code>.');
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| 
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| ```
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| 
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| </section>
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| 
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| ## Challenge Seed
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| <section id='challengeSeed'>
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| 
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| <div id='jsx-seed'>
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| 
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| ```jsx
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| class MyComponent 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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|       display: true
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|     }
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|     this.toggleDisplay = this.toggleDisplay.bind(this);
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|   }
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|   toggleDisplay() {
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|     this.setState({
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|       display: !this.state.display
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|     });
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|   }
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|   render() {
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|     // change code below this line
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| 
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|     return (
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|        <div>
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|          <button onClick={this.toggleDisplay}>Toggle Display</button>
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|          <h1>Displayed!</h1>
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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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| </div>
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| 
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| 
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| ### After Test
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| <div id='jsx-teardown'>
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| 
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| ```js
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| ReactDOM.render(<MyComponent />, document.getElementById('root'))
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| ```
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| 
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| </div>
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| 
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| </section>
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| 
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| ## Solution
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| <section id='solution'>
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| 
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| 
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| ```js
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| class MyComponent 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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|       display: true
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|     }
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|  this.toggleDisplay = this.toggleDisplay.bind(this);
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|  }
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|   toggleDisplay() {
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|     this.setState({
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|       display: !this.state.display
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|     });
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|   }
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|   render() {
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|     // change code below this line
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|     if (this.state.display) {
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|       return (
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|          <div>
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|            <button onClick={this.toggleDisplay}>Toggle Display</button>
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|            <h1>Displayed!</h1>
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|          </div>
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|       );
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|     } else {
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|       return (
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|         <div>
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|            <button onClick={this.toggleDisplay}>Toggle Display</button>
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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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| 
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| </section>
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