使用react context 实现vue插槽slot功能

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 = () => null
AddOn.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脚本之家网站的支持！
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