React中编写CSS实例详解

import React, { PureComponent } from 'react'
export class App extends PureComponent {
  constructor(props) {
    super(props)
    this.state = {
      color: 'red'
    }
  }
  render() {
    return (
      <div style={{ colot: this.state.color, backgroundColor: 'skyblue' }}>App</div>
    )
  }
}
export default App

import React, { PureComponent } from 'react'
import './style.css'
export class App extends PureComponent {
  constructor(props) {
    super(props)
    this.state = {
      color: 'red'
    }
  }
  render() {
    return (
      <div>App</div>
    )
  }
}
export default App

import React, { PureComponent } from 'react'
// 引入css modules - 实际会将对应的css文件编译为一个JS对象
// 当我们将一个样式文件的后缀名修改为 .module.css的时候，对应样式文件就变成了css样式模块
import AppStyle from './style.module.css'
export class App extends PureComponent {
  constructor(props) {
    super(props)
    this.state = {
      color: 'red'
    }
  }
  render() {
    return (
      <div>
				{}
				<h2 className={AppStyle.title}>title</h2>
				{}
				<p className={AppStyle.content}>content</p>
			</div>
    )
  }
}
export default App

npm install styled-components

import React, { PureComponent } from 'react'
// 使用css in js后，对应的样式直接编写在js文件中即可
import AppWrapper from './style.js'
export class App extends PureComponent {
  render() {
    return (
      <AppWrapper>
				<h2 className="title">title</h2>
				<p className="content">content</p>
			</AppWrapper>
    )
  }
}
export default App

import styled from 'styled-components'
// styled.div本质上是一个函数  需要通过标签模板字符串进行调用 并返回一个新的有对应样式的组件
// ps: 默认情况下对应样式是不会高亮的，需要高亮可以安装vscode-styled-components插件
export default styled.div`
	
	
	
	
	
	background-color: #f5f5f5;
	
	.title {
		color: red;
		&:hover {
			background-color: gray;
		}
	}
	
	.content {
		color: skyblue
	}
`

import styled from 'styled-components'
export default styled.div`
	background-color: #f5f5f5;
	.content {
		color: skyblue
	}
`
// 如果某一块的样式比较多，可以将对应的样式进行单独抽离
// 形成一个独立的样式组件
export const TitleWrapper = styled.h2`
	color: red;
	&:hover {
		background-color: gray;
	}
`

import React, { PureComponent } from 'react'
import AppWrapper from './style.js'
export class App extends PureComponent {
	constructor(props) {
		super(props)
		this.state = {
			color: 'skyblue'
		}
	}
  render() {
    return (
			// AppWrapper本质上是一个组件
			// 所以对应的样式直接以props的形式进行传入即可
      <AppWrapper color={ this.state.color }>
				<h2 className="title">title</h2>
				<p className="content">content</p>
			</AppWrapper>
    )
  }
}
export default App

import styled from 'styled-components'
export default styled.div`
	.title {
		
		color: ${ props => props.color };
		&:hover {
			background-color: gray;
		}
	}
	.content {
		color: gray
	}
`

import styled from 'styled-components'
// 因为styled-components 本质上就是css in js
// 所以我们也可以通过如下方式来使用styled-components
export default styled.div`
	.title {
		// 解构语法
		color: ${ ({ color }) => color };
		&:hover {
		  // 解构的时候 设置对应的默认值
			background-color: ${ ({ bGColor = 'yellow' }) => bgColor };
		}
	}
	.content {
	 	// 空值合并操作符
		color: ${ ({ contentColor }) => contentColor ?? 'orange' }
	}
`

import styled from 'styled-components'
// attrs方法会返回对应的含有样式的样式组件
// 所以在这里可以链式调用
// 在attrs中可以传入一个回调函数，用于设置对应的默认值
// 回调函数在被调用的时候会将对应的props传递过来
export default styled.div.attrs(props => ({
	contentColor: props.contentColor ?? 'purple'
}))`
	.title {
		color: ${ props => props.color };
		&:hover {
			background-color: gray;
		}
	}
	.content {
		color: ${ props => props.contentColor }
	}
`

export const primaryColor = '#409eff'
export const warnColor = '#e6a23c'
export const successColor = '#67c23a'

import styled from 'styled-components'
import {
	primaryColor,
	successColor
} from '../style/theme'
export default styled.div`
	.title {
		color: ${ successColor };
		&:hover {
			background-color: gray;
		}
	}
	.content {
		color: ${ primaryColor }
	}
`

import ReactDOM from 'react-dom/client'
import App from './App'
import { StrictMode } from 'react'
import { ThemeProvider } from 'styled-components';
ReactDOM.createRoot(document.querySelector('#root')).render(
	<StrictMode>
		{}
		<ThemeProvider theme={{ color: 'skyblue' }}>
			<App />
		</ThemeProvider>
	</StrictMode>
)

import styled from 'styled-components'
export default styled.div`
	.title {
		
		color: ${ props => props.theme.color };
	}
	.content {
		color: red
	}
`

const OriginButton = styled.button`
	border-radius: 5px;
`
export const PrimaryButton = styled(OriginButton)`
	color: #fff;
	background-color: #409eff;
`

import React, { PureComponent } from 'react'
export class App extends PureComponent {
	constructor(props) {
		super(props)
		this.state = {
			isActive: true,
			isCurrent: true
		}
	}
	render() {
		const { isActive, isCurrent } = this.state
		return (
			<div>
				<div className={ `${isActive ? 'active' : '' } ${ isCurrent ? 'current' : '' }` }>active</div>
			</div>
		)
	}
}
export default App

import React, { PureComponent } from 'react'
export class App extends PureComponent {
	constructor(props) {
		super(props)
		this.state = {
			isActive: true,
			isCurrent: true
		}
	}
	render() {
		const { isActive, isCurrent } = this.state
		const activeClass = []
		if (isActive) {
			activeClass.push('active')
		}
		if (isCurrent) {
			activeClass.push('current')
		}
		return (
			<div>
				<div className={ activeClass.join(' ') }>active</div>
			</div>
		)
	}
}
export default App

npm install classnames

classNames('foo', 'bar'); // => 'foo bar'
classNames('foo', { bar: true }); // => 'foo bar'
classNames({ 'foo-bar': true }); // => 'foo-bar'
classNames({ 'foo-bar': false }); // => ''
classNames({ foo: true }, { bar: true }); // => 'foo bar'
classNames({ foo: true, bar: true }); // => 'foo bar'
// classnames 支持多种编写方式 混合使用
classNames('foo', { bar: true, duck: false }, 'baz', { quux: true }); // => 'foo bar baz quux'
// 只要是falsy值的结果 全部都会被忽略
classNames(null, false, 'bar', undefined, 0, 1, { baz: null }, ''); // => 'bar 1'
// classnames 支持 数组写法 和 计算属性名
className={ classnames([{ [activeClass]: isActive }, { current: isCurrent }])