freeCodeCamp/curriculum/challenges/chinese/03-front-end-libraries/react/use-react-to-render-nested-...

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---
id: 5a24c314108439a4d4036165
challengeType: 6
forumTopicId: 301420
2020-10-01 15:54:21 +00:00
title: 使用 React 渲染嵌套组件
---
## Description
<section id='description'>
上一个挑战显示了组合两个组件的简单方法,但是有许多不同的方法可以把 React 组件组合在一起。
组件组合是 React 的强大功能之一。当你使用 React 时,应当先用组件的思路考虑清楚用户界面的结构(如上一个挑战中的 App 示例)。可以将 UI 分解为基本的构建块,这些构建块就是组件。这样做有助于将负责 UI 的代码与负责处理应用程序逻辑的代码分开,并可以大大简化复杂项目的开发和维护。
</section>
## Instructions
<section id='instructions'>
代码编辑器中定义了两个功能组件,分别是<code>TypesOfFruit</code><code>Fruits</code>。请把<code>TypesOfFruit</code>组件放到<code>Fruits</code>组件中,然后把<code>Fruits</code>组件放到<code>TypesOfFood</code>组件中。结果应该是子组件嵌套在父组件中,父组件嵌套在它本身的父组件中!
</section>
## Tests
<section id='tests'>
```yml
tests:
- text: <code>TypesOfFood</code>组件应该返回单个<code>div</code>元素。
testString: assert(Enzyme.shallow(React.createElement(TypesOfFood)).type() === 'div');
- text: <code>TypesOfFood</code>组件应该返回<code>Fruits</code>组件。
testString: assert(Enzyme.shallow(React.createElement(TypesOfFood)).props().children[1].type.name === 'Fruits');
- text: <code>Fruits</code>组件应该返回<code>TypesOfFruit</code>组件。
testString: assert(Enzyme.mount(React.createElement(TypesOfFood)).find('h2').html() === '<h2>Fruits:</h2>');
- text: <code>TypesOfFruit</code>组件应该返回<code>h2</code><code>ul</code>元素。
testString: assert(Enzyme.mount(React.createElement(TypesOfFood)).find('ul').text() === 'ApplesBlueberriesStrawberriesBananas');
```
</section>
## Challenge Seed
<section id='challengeSeed'>
<div id='jsx-seed'>
```jsx
const TypesOfFruit = () => {
return (
<div>
<h2>Fruits:</h2>
<ul>
<li>Apples</li>
<li>Blueberries</li>
<li>Strawberries</li>
<li>Bananas</li>
</ul>
</div>
);
};
const Fruits = () => {
return (
<div>
{ /* change code below this line */ }
{ /* change code above this line */ }
</div>
);
};
class TypesOfFood extends React.Component {
constructor(props) {
super(props);
}
render() {
return (
<div>
<h1>Types of Food:</h1>
{ /* change code below this line */ }
{ /* change code above this line */ }
</div>
);
}
};
```
</div>
### After Test
<div id='jsx-teardown'>
```js
ReactDOM.render(<TypesOfFood />, document.getElementById('root'))
```
</div>
</section>
## Solution
<section id='solution'>
```js
const TypesOfFruit = () => {
return (
<div>
<h2>Fruits:</h2>
<ul>
<li>Apples</li>
<li>Blueberries</li>
<li>Strawberries</li>
<li>Bananas</li>
</ul>
</div>
);
};
const Fruits = () => {
return (
<div>
{ /* change code below this line */ }
<TypesOfFruit />
{ /* change code above this line */ }
</div>
);
};
class TypesOfFood extends React.Component {
constructor(props) {
super(props);
}
render() {
return (
<div>
<h1>Types of Food:</h1>
{ /* change code below this line */ }
<Fruits />
{ /* change code above this line */ }
</div>
);
}
};
```
</section>