140 lines
4.4 KiB
Markdown
140 lines
4.4 KiB
Markdown
---
|
||
id: 5a24c314108439a4d4036167
|
||
challengeType: 6
|
||
forumTopicId: 301404
|
||
title: 渲染 class 组件为 Dom 树
|
||
---
|
||
|
||
## Description
|
||
<section id='description'>
|
||
你可能还记得在早期挑战中使用 ReactDOM API 将 JSX 元素渲染到 DOM，这与渲染 React 组件的过程十分相似。过去的几个挑战主要针对组件和组合，因此渲染是在幕后为你完成的。但是，如果不调用 ReactDOM API，你编写的任何 React 代码都不会渲染到 DOM。
|
||
以下是语法的复习：<code>ReactDOM.render(componentToRender, targetNode)</code>。第一个参数是要渲染的 React 组件。第二个参数是要在其中渲染该组件的 DOM 节点。
|
||
React 组件传递到<code>ReactDOM.render()</code>与 JSX 元素略有不同。对于 JSX 元素，你传入的是要渲染的元素的名称。但是，对于 React 组件，你需要使用与渲染嵌套组件相同的语法，例如<code>ReactDOM.render(<ComponentToRender />, targetNode)</code>。你可以将此语法用于ES6类组件和函数组件。
|
||
</section>
|
||
|
||
## Instructions
|
||
<section id='instructions'>
|
||
在后台为你定义了<code>Fruits</code>和<code>Vegetables</code>组件。将两个组件渲染为<code>TypesOfFood</code>组件的子组件，然后将<code>TypesOfFood</code>渲染到 DOM 节点，在这个挑战中，请渲染到 id 为<code>challenge-node</code>的<code>div</code>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((function() { const mockedComponent = Enzyme.mount(React.createElement(TypesOfFood)); return mockedComponent.children().type() === 'div'; })());
|
||
- text: <code>TypesOfFood</code>组件应该在<code>h1</code>元素之后渲染<code>Fruits</code>组件。
|
||
testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(TypesOfFood)); return mockedComponent.children().childAt(1).name() === 'Fruits'; })());
|
||
- text: <code>TypesOfFood</code>组件应该在<code>Fruits</code>组件之后渲染<code>Vegetables</code>组件。
|
||
testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(TypesOfFood)); return mockedComponent.children().childAt(2).name() === 'Vegetables'; })());
|
||
- text: <code>TypesOfFood</code>组件应该渲染到 id 为<code>challenge-node</code>的<code>div</code>中。
|
||
testString: assert((function() { const html = document.getElementById('challenge-node').childNodes[0].innerHTML; return html.includes('<div><h2>Fruits:</h2><h4>Non-Citrus:</h4><ul><li>Apples</li><li>Blueberries</li><li>Strawberries</li><li>Bananas</li></ul><h4>Citrus:</h4><ul><li>Lemon</li><li>Lime</li><li>Orange</li><li>Grapefruit</li></ul></div>') && html.includes('<div><h2>Vegetables:</h2><ul><li>Brussel Sprouts</li><li>Broccoli</li><li>Squash</li></ul></div>'); })());
|
||
|
||
```
|
||
|
||
</section>
|
||
|
||
## Challenge Seed
|
||
<section id='challengeSeed'>
|
||
|
||
<div id='jsx-seed'>
|
||
|
||
```jsx
|
||
|
||
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>
|
||
);
|
||
}
|
||
};
|
||
|
||
// change code below this line
|
||
|
||
```
|
||
|
||
</div>
|
||
|
||
### Before Test
|
||
<div id='jsx-setup'>
|
||
|
||
```jsx
|
||
|
||
const Fruits = () => {
|
||
return (
|
||
<div>
|
||
<h2>Fruits:</h2>
|
||
<h4>Non-Citrus:</h4>
|
||
<ul>
|
||
<li>Apples</li>
|
||
<li>Blueberries</li>
|
||
<li>Strawberries</li>
|
||
<li>Bananas</li>
|
||
</ul>
|
||
<h4>Citrus:</h4>
|
||
<ul>
|
||
<li>Lemon</li>
|
||
<li>Lime</li>
|
||
<li>Orange</li>
|
||
<li>Grapefruit</li>
|
||
</ul>
|
||
</div>
|
||
);
|
||
};
|
||
const Vegetables = () => {
|
||
return (
|
||
<div>
|
||
<h2>Vegetables:</h2>
|
||
<ul>
|
||
<li>Brussel Sprouts</li>
|
||
<li>Broccoli</li>
|
||
<li>Squash</li>
|
||
</ul>
|
||
</div>
|
||
);
|
||
};
|
||
|
||
```
|
||
|
||
</div>
|
||
|
||
|
||
</section>
|
||
|
||
## Solution
|
||
<section id='solution'>
|
||
|
||
|
||
```js
|
||
class TypesOfFood extends React.Component {
|
||
constructor(props) {
|
||
super(props);
|
||
}
|
||
render() {
|
||
return (
|
||
<div>
|
||
<h1>Types of Food:</h1>
|
||
{/* change code below this line */}
|
||
<Fruits />
|
||
<Vegetables />
|
||
{/* change code above this line */}
|
||
</div>
|
||
);
|
||
}
|
||
};
|
||
|
||
// change code below this line
|
||
ReactDOM.render(<TypesOfFood />, document.getElementById('challenge-node'));
|
||
```
|
||
|
||
</section>
|