首先来看下vue的slot的实现

<base-layout>组件，具名插槽name定义以及默认插槽

<div class="container"> <header> <slot name="header"></slot> </header> <main> <slot></slot> </main> <footer> <slot name="footer"></slot> </footer></div><template>

提供内容渲染的组件

<base-layout> <template v-slot:header> <h1>Here might be a page title</h1> </template> <p>A paragraph for the main content.</p> <p>And another one.</p> <template v-slot:footer> <p>Here's some contact info</p> </template></base-layout>

最终会渲染出已下架结构

<base-layout> <template v-slot:header> <h1>Here might be a page title</h1> </template> <p>A paragraph for the main content.</p> <p>And another one.</p> <template v-slot:footer> <p>Here's some contact info</p> </template></base-layout>

言归正传，怎样使用react的context实现vue的这一功能呢

1 首先确认下layout组件的结构

import React, { Component } from 'react';import SlotProvider from './SlotProvider'import Slot from './Slot'class AppLayout extends Component { static displayName = 'AppLayout' render () { return ( <div className="container"> <header> <Slot name="header"></Slot> </header> <main> <Slot></Slot> </main> <footer> <Slot name="footer"></Slot> </footer> </div> ) }}export default SlotProvider(AppLayout)

2 对此结构输出具体内容的组件

import React, { Component } from 'react';import AppLayout from './AppLayout'import AddOn from './AddOn'export default class App extends Component { render() { return ( <AppLayout> <AddOn slot="header"> <h1>这里可能是一个页面标题</h1> </AddOn> <AddOn> <p>主要内容的一个段落。</p> <p>另一个段落。</p> </AddOn> <AddOn slot="footer"> <p>这里有一些联系信息</p> </AddOn> </AppLayout> ) }}

3 其中AddOn类似于上面vue的template，所以下面来实现这个简单的只是用来提供slot标识和children内容的组件AddOn的实现

import React from 'react';import PropTypes from 'prop-types'const AddOn = () => nullAddOn.propTypes = { slot: PropTypes.string }AddOn.defaultTypes = { slot: '$$default' }AddOn.displayName = 'AddOn'export default AddOn

4 Slot组件

import React from 'react';import { SlotContext } from './SlotProvider'import PropTypes from 'prop-types'const Slot = ({ name, children }) => { return ( <SlotContext.Consumer> {(value) => { const addOnRenderer = value.requestAddOnRenderer(name) return (addOnRenderer && addOnRenderer()) || children || null }} </SlotContext.Consumer> )}Slot.displayName = 'Slot'Slot.propTypes = { name: PropTypes.string }Slot.defaultProps = { name: '$$default' }export default Slot

5 接下来就是对Slot进行解析的HOC SlotProvider组件了

import React, { Component } from 'react';function getDisplayName(component) { return component.displayName || component.name || 'component'}export const SlotContext = React.createContext({ requestAddOnRenderer: () => { }})const SlotProviderHoC = (WrappedComponent) => { return class extends Component { static displayName = `SlotProvider(${getDisplayName(WrappedComponent)})` // 用于缓存每个<AddOn />的内容 addOnRenderers = {} requestAddOnRenderer = (name) => { if (!this.addOnRenderers[name]) { return undefined } return () => ( this.addOnRenderers[name] ) } render() { const { children, ...restProps } = this.props if (children) { // 以k-v的方式缓存<AddOn />的内容 const arr = React.Children.toArray(children) const nameChecked = [] this.addOnRenderers = {} arr.forEach(item => { const itemType = item.type console.log('itemType',itemType) if (item.type.displayName === 'AddOn') { const slotName = item.props.slot || '$$default' // 确保内容唯一性 if (nameChecked.findIndex(item => item === slotName) !== -1) { throw new Error(`Slot(${slotName}) has been occupied`) } this.addOnRenderers[slotName] = item.props.children nameChecked.push(slotName) } }) } return ( <SlotContext.Provider value={{ requestAddOnRenderer: this.requestAddOnRenderer }}> <WrappedComponent {...restProps} /> </SlotContext.Provider > ) } } } export default SlotProviderHoC

6 最终渲染结果

总结

以上所述是小编给大家介绍的使用react context 实现vue插槽slot功能,希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！
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