npm install --save styled-components

<script src="https://unpkg.com/styled-components/dist/styled-components.min.js"></script>

const Component = window.styled.div`
  color: red;
`

// 创建一个 Title 组件,它将渲染一个附加了样式的 <h1> 标签
const Title = styled.h1`
  font-size: 1.5em;
  text-align: center;
  color: palevioletred;
`;
// 创建一个 Wrapper 组件,它将渲染一个附加了样式的 <section> 标签
const Wrapper = styled.section`
  padding: 4em;
  background: papayawhip;
`;
// 就像使用常规 React 组件一样使用 Title 和 Wrapper 
render(
  <Wrapper>
    <Title>
      Hello World!
    </Title>
  </Wrapper>
);

const Button = styled.button`
  /* Adapt the colors based on primary prop */
  background: ${props => props.primary ? "palevioletred" : "white"};
  color: ${props => props.primary ? "white" : "palevioletred"};
  font-size: 1em;
  margin: 1em;
  padding: 0.25em 1em;
  border: 2px solid palevioletred;
  border-radius: 3px;
`;
render(
  <div>
    <Button>Normal</Button>
    <Button primary>Primary</Button>
  </div>
);

// 上一节创建的没有插值的 Button 组件
const Button = styled.button`
  color: palevioletred;
  font-size: 1em;
  margin: 1em;
  padding: 0.25em 1em;
  border: 2px solid palevioletred;
  border-radius: 3px;
`;
// 一个继承 Button 的新组件, 重载了一部分样式
const TomatoButton = styled(Button)`
  color: tomato;
  border-color: tomato;
`;
render(
  <div>
    <Button>Normal Button</Button>
    <TomatoButton>Tomato Button</TomatoButton>
  </div>
);

const Button = styled.button`
  display: inline-block;
  color: palevioletred;
  font-size: 1em;
  margin: 1em;
  padding: 0.25em 1em;
  border: 2px solid palevioletred;
  border-radius: 3px;
`;
const TomatoButton = styled(Button)`
  color: tomato;
  border-color: tomato;
`;
render(
  <div>
    <Button>Normal Button</Button>
    <Button as="a" href="/">Link with Button styles</Button>
    <TomatoButton as="a" href="/">Link with Tomato Button styles</TomatoButton>
  </div>
);

const Button = styled.button`
  display: inline-block;
  color: palevioletred;
  font-size: 1em;
  margin: 1em;
  padding: 0.25em 1em;
  border: 2px solid palevioletred;
  border-radius: 3px;
`;
const ReversedButton = props => <button {...props} children={props.children.split('').reverse()} />
render(
  <div>
    <Button>Normal Button</Button>
    <Button as={ReversedButton}>Custom Button with Normal Button styles</Button>
  </div>
);

// 下面是给 react-router-dom  Link 组件添加样式的示例
const Link = ({ className, children }) => (
  <a className={className}>
    {children}
  </a>
);
const StyledLink = styled(Link)`
  color: palevioletred;
  font-weight: bold;
`;
render(
  <div>
    <Link>Unstyled, boring Link</Link>
    <br />
    <StyledLink>Styled, exciting Link</StyledLink>
  </div>
);

// 创建一个给<input>标签添加若干样式的 Input 组件 
const Input = styled.input`
  padding: 0.5em;
  margin: 0.5em;
  color: ${props => props.inputColor || "palevioletred"};
  background: papayawhip;
  border: none;
  border-radius: 3px;
`;
// 渲染两个样式化的 text input,一个标准颜色,一个自定义颜色
render(
  <div>
    <Input defaultValue="@probablyup" type="text" />
    <Input defaultValue="@geelen" type="text" inputColor="rebeccapurple" />
  </div>
);

Coming from CSS

styled-components 如何在组件中工作?

如果你熟悉在组件中导入 CSS(例如 CSSModules),那么下面的写法你一定不陌生:

import React from 'react'
import styles from './styles.css'
export default class Counter extends React.Component {
  state = { count: 0 }
  increment = () => this.setState({ count: this.state.count + 1 })
  decrement = () => this.setState({ count: this.state.count - 1 })
  render() {
    return (
      <div className={styles.counter}>
        <p className={styles.paragraph}>{this.state.count}</p>
        <button className={styles.button} onClick={this.increment}>
          +
        </button>
        <button className={styles.button} onClick={this.decrement}>
          -
        </button>
      </div>
    )
  }
}

由于 Styled Component 是 HTML 元素和作用在元素上的样式规则的组合, 我们可以这样编写Counter:

import React from 'react'
import styled from 'styled-components'
const StyledCounter = styled.div`
  /* ... */
`
const Paragraph = styled.p`
  /* ... */
`
const Button = styled.button`
  /* ... */
`
export default class Counter extends React.Component {
  state = { count: 0 }
  increment = () => this.setState({ count: this.state.count + 1 })
  decrement = () => this.setState({ count: this.state.count - 1 })
  render() {
    return (
      <StyledCounter>
        <Paragraph>{this.state.count}</Paragraph>
        <Button onClick={this.increment}>+</Button>
        <Button onClick={this.decrement}>-</Button>
      </StyledCounter>
    )
  }
}

注意,我们在StyledCounter添加了”Styled”前缀,这样组件Counter 和StyledCounter 不会明明冲突,而且可以在 React Developer Tools 和 Web Inspector 中轻松识别.

在 render 方法之外定义 Styled Components

在 render 方法之外定义 styled component 很重要, 不然 styled component 会在每个渲染过程中重新创建. 这将阻止缓存生效并且大大降低了渲染速度,所以尽量避免这种情况.

推荐通过以下方式创建 styled components :

const StyledWrapper = styled.div`
  /* ... */
`
const Wrapper = ({ message }) => {
  return <StyledWrapper>{message}</StyledWrapper>
}

而不是:

const Wrapper = ({ message }) => {
  // WARNING: 别这么干,会很慢!!!
  const StyledWrapper = styled.div`
    /* ... */
  `
  return <StyledWrapper>{message}</StyledWrapper>
}

推荐阅读:Talia Marcassa 写了一篇很精彩的有关styled-components实际应用的文章,包含许多实用的见解以及与其它方案的比较Styled Components: To Use or Not to Use?

伪元素,伪类选择器和嵌套

styled-component 所使用的预处理器stylis支持自动嵌套的 scss-like 语法,示例如下:

const Thing = styled.div`
  color: blue;
`

伪元素和伪类无需进一步细化,而是自动附加到了组件:

const Thing = styled.button`
  color: blue;
  ::before {
    content: '🚀';
  }
  :hover {
    color: red;
  }
`
render(
  <Thing>Hello world!</Thing>
)

对于更复杂的选择器,可以使用与号(&)来指向主组件.以下是一些示例:

const Thing = styled.div.attrs({ tabIndex: 0 })`
  color: blue;
  &:hover {
    color: red; // <Thing> when hovered
  }
  & ~ & {
    background: tomato; // <Thing> as a sibling of <Thing>, but maybe not directly next to it
  }
  & + & {
    background: lime; // <Thing> next to <Thing>
  }
  &.something {
    background: orange; // <Thing> tagged with an additional CSS class ".something"
  }
  .something-else & {
    border: 1px solid; // <Thing> inside another element labeled ".something-else"
  }
`
render(
  <React.Fragment>
    <Thing>Hello world!</Thing>
    <Thing>How ya doing?</Thing>
    <Thing className="something">The sun is shining...</Thing>
    <div>Pretty nice day today.</div>
    <Thing>Don't you think?</Thing>
    <div className="something-else">
      <Thing>Splendid.</Thing>
    </div>
  </React.Fragment>
)

如果只写选择器而不带&,则指向组件的子节点.

const Thing = styled.div`
  color: blue;
  .something {
    border: 1px solid; // an element labeled ".something" inside <Thing>
    display: block;
  }
`
render(
  <Thing>
    <label htmlFor="foo-button" className="something">Mystery button</label>
    <button id="foo-button">What do I do?</button>
  </Thing>
)

最后,&可以用于增加组件的差异性;在处理混用 styled-components 和纯 CSS 导致的样式冲突时这将会非常有用:

const Thing = styled.div`
  && {
    color: blue;
  }
`
const GlobalStyle = createGlobalStyle`
  div${Thing} {
    color: red;
  }
`
render(
  <React.Fragment>
    <GlobalStyle />
    <Thing>
      I'm blue, da ba dee da ba daa
    </Thing>
  </React.Fragment>
)

附加额外的属性 (v2)

为了避免仅为传递一些props来渲染组件或元素而使用不必要的wrapper, 可以使用 .attrs constructor. 通过它可以添加额外的 props 或 attributes 到组件.

举例来说,可以通过这种方式给元素添加静态 props,或者传递第三方 prop 给组件(比如传递activeClassName给 React Router 的 Link). 此外也可以将dynamic props 添加到组件. .attrs 对象也接收函数,返回值也将合并进 props.

示例如下:

const Input = styled.input.attrs({
  //  static props
  type: "password",
  //  dynamic props
  margin: props => props.size || "1em",
  padding: props => props.size || "1em"
})`
  color: palevioletred;
  font-size: 1em;
  border: 2px solid palevioletred;
  border-radius: 3px;
  /* dynamically computed props */
  margin: ${props => props.margin};
  padding: ${props => props.padding};
`;
render(
  <div>
    <Input placeholder="A small text input" size="1em" />
    <br />
    <Input placeholder="A bigger text input" size="2em" />
  </div>
);

正如所见,我们可以在插值中访问新创建的 props,type attribute也正确的传递给了元素.

动画

虽然使用@keyframes的 CSS 动画不限于单个组件,但我们仍希望它们不是全局的(以避免冲突). 这就是为什么 styled-components 导出 keyframes helper 的原因: 它将生成一个可以在 APP 应用的唯一实例:

// Create the keyframes
const rotate = keyframes`
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
`;
// Here we create a component that will rotate everything we pass in over two seconds
const Rotate = styled.div`
  display: inline-block;
  animation: ${rotate} 2s linear infinite;
  padding: 2rem 1rem;
  font-size: 1.2rem;
`;

注意

react-native不支持 keyframes. 请参考ReactNative.Animated API.

Keyframes are lazily injected when they’re used, which is how they can be code-splitted, so you have to use the css helper for shared style fragments:

const rotate = keyframes``
// ❌ This will throw an error!
const styles = `
  animation: ${rotate} 2s linear infinite;
`;
// ✅ This will work as intended
const styles = css`
  animation: ${rotate} 2s linear infinite;
`

NOTE

This used to work in v3 and below where we didn’t code-split keyframes. If you’re upgrading from v3, make sure that all your shared style fragments are using the css helper!

ReactNative

styled-components 可以在 React-Native 中以同样的方式使用. 示例: Snack by Expo.

import React from 'react'
import styled from 'styled-components/native'
const StyledView = styled.View`
  background-color: papayawhip;
`
const StyledText = styled.Text`
  color: palevioletred;
`
class MyReactNativeComponent extends React.Component {
  render() {
    return (
      <StyledView>
        <StyledText>Hello World!</StyledText>
      </StyledView>
    )
  }
}

同时也支持复杂样式 (like transform)和简写(如 margin) 感谢 css-to-react-native !

注意

flex的工作方式类似于 CSS 简写, 而不是 React Native 中的flex用法. 设置 flex: 1 则会设置 flexShrink为1.

Imagine how you’d write the property in React Native, guess how you’d transfer it to CSS, and you’re probably right:

const RotatedBox = styled.View`
  transform: rotate(90deg);
  text-shadow-offset: 10px 5px;
  font-variant: small-caps;
  margin: 5px 7px 2px;
`

与 web-version 不同, React Native 不支持 keyframes 和 createGlobalStyle .使用媒体查询或是嵌套 CSS 也会报警.

NOTE

v2 支持百分比. 为了实现这一目标,需要为所有简写强制指定单位. 如果要迁移到v2, a codemod is available.

Simpler usage with the metro bundler

If you’d prefer to just import styled-components instead of styled-components/native, you can add a resolverMainFields configuration that includes “react-native“. This used to be supported in metro by default (and currently does work in haul) but appears to have been removed at some point.