94 lines
5.5 KiB
Markdown
94 lines
5.5 KiB
Markdown
---
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id: 5a24c314108439a4d403616a
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title: Pass an Array as Props
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challengeType: 6
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isRequired: false
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videoUrl: ''
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localeTitle: 将数组作为道具传递
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---
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## Description
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<section id="description">最后一项挑战演示了如何将信息从父组件传递到子组件作为<code>props</code>或属性。这个挑战着眼于如何将数组作为<code>props</code>传递。要将数组传递给JSX元素，必须将其视为JavaScript并用大括号括起来。 <blockquote> <为父级> <br> <ChildComponent colors = {[“green”，“blue”，“red”]} /> <br> </为父级> </blockquote>然后子组件可以访问数组属性<code>colors</code> 。访问属性时可以使用诸如<code>join()</code>类的数组方法。 <code>const ChildComponent = (props) => <p>{props.colors.join(', ')}</p></code>这会将所有<code>colors</code>数组项连接成逗号分隔的字符串并生成： <code><p>green, blue, red</p></code>稍后，我们将了解在React中呈现数据数组的其他常用方法。 </section>
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## Instructions
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<section id="instructions">代码编辑器中有<code>List</code>和<code>ToDo</code>组件。从<code>ToDo</code>组件渲染每个<code>List</code> ，传入分配给待办任务数组的<code>tasks</code>属性，例如<code>["walk dog", "workout"]</code> 。然后在<code>List</code>组件中访问此<code>tasks</code>数组，在<code>p</code>元素中显示其值。使用<code>join(", ")</code>以逗号分隔列表的形式显示<code>p</code>元素中的<code>props.tasks</code>数组。今天的列表应该至少有2个任务，明天应该至少有3个任务。 </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>ToDo</code>组件应返回单个外部<code>div</code> 。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(ToDo)); return mockedComponent.children().first().type() === "div"; })(), "The <code>ToDo</code> component should return a single outer <code>div</code>.");'
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- text: <code>ToDo</code>组件的第三个子<code>ToDo</code>应该是<code>List</code>组件的实例。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(ToDo)); return mockedComponent.children().first().childAt(2).name() === "List"; })(), "The third child of the <code>ToDo</code> component should be an instance of the <code>List</code> component.");'
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- text: <code>ToDo</code>组件的第五个子<code>ToDo</code>应该是<code>List</code>组件的一个实例。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(ToDo)); return mockedComponent.children().first().childAt(4).name() === "List"; })(), "The fifth child of the <code>ToDo</code> component should be an instance of the <code>List</code> component.");'
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- text: <code>List</code>组件的两个实例都应该有一个名为<code>tasks</code>的属性，而<code>tasks</code>应该是array类型。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(ToDo)); return Array.isArray(mockedComponent.find("List").get(0).props.tasks) && Array.isArray(mockedComponent.find("List").get(1).props.tasks); })(), "Both instances of the <code>List</code> component should have a property called <code>tasks</code> and <code>tasks</code> should be of type array.");'
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- text: 表示今天任务的第一个<code>List</code>组件应该有2个或更多项。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(ToDo)); return mockedComponent.find("List").get(0).props.tasks.length >= 2; })(), "The first <code>List</code> component representing the tasks for today should have 2 or more items.");'
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- text: 表示明天任务的第二个<code>List</code>组件应该有3个或更多项。
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(ToDo)); return mockedComponent.find("List").get(1).props.tasks.length >= 3; })(), "The second <code>List</code> component representing the tasks for tomorrow should have 3 or more items.");'
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- text: '<code>List</code>组件应该将<code>p</code>标记中的<code>tasks</code> prop的值呈现为以逗号分隔的列表，例如<code>walk dog, workout</code> 。'
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testString: 'assert((function() { const mockedComponent = Enzyme.mount(React.createElement(ToDo)); return mockedComponent.find("p").get(0).props.children === mockedComponent.find("List").get(0).props.tasks.join(", ") && mockedComponent.find("p").get(1).props.children === mockedComponent.find("List").get(1).props.tasks.join(", "); })(), "The <code>List</code> component should render the value from the <code>tasks</code> prop in the <code>p</code> tag as a comma separated list, for example <code>walk dog, workout</code>.");'
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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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const List= (props) => {
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{ /* change code below this line */ }
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return <p>{}</p>
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{ /* change code above this line */ }
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};
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class ToDo 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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<h1>To Do Lists</h1>
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<h2>Today</h2>
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{ /* change code below this line */ }
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<List/>
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<h2>Tomorrow</h2>
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<List/>
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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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</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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