最近在重构公司老项目,由于本人以前的技术栈是vue, 换工作后发现现在公司的技术栈是react, 所以重构的过程是及其痛苦。加之项目又是几年前的老项目,不敢大改,比葫芦画瓢比比皆是。本文就介绍下遇到的一个常用的痛点。欢迎大佬指正。
废话不多说,直接上一段代码。
import React from 'react' const App = () => { const record = { toKe: true, // 贝壳首页 toSecondHand: true, // 二手房 toFang: true, // 新房 } return ( <div style={{width: 600, margin: '50px auto'}}> <ul> <li> <h3>react常规写法</h3> { record.toKe "https://bj.ke.com" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >贝壳首页</a> : null } { record.toSecondHand "https://bj.ke.com/ershoufang/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >二手房</a> : null } { record.toFang "https://bj.fang.ke.com/loupan/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >新房</a> : null } </li> </ul> </div> ) } export default App
如上述代码,我们在项目中会遇到很多这样的写法, 细看一下没什么问题,可是当在重构老项目的时候,你会发现这个代码结构是多么痛苦,特别是如下的结构。
{ record.toFang && record.toKe && record.toSecondHand && <div> <a style={{padding: 20}} href="https://bj.ke.com" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >贝壳首页</a> <a style={{padding: 20}} href="https://bj.ke.com/ershoufang/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >二手房</a> <a style={{padding: 20}} href="https://bj.fang.ke.com/loupan/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >新房</a> </div> }
虽然代码逻辑没问题,但人生就是这样,有时候出场顺序真的很重要。突然就想起vue的v-if了。
没错,回归主题,就是:react中模拟vue的v-if
先上代码
import React from 'react' import Hidden from './Hidden' const App = () => { const record = { toKe: true, // 贝壳首页 toSecondHand: true, // 二手房 toFang: true, // 新房 } return ( <div style={{width: 600, margin: '50px auto'}}> <ul> <li> <h3>react模拟实现vue中v-if指令</h3> <Hidden visible={record.toKe} tag='span'> <a href="https://bj.ke.com" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >贝壳首页</a> </Hidden> <Hidden visible={record.toSecondHand} tag='span' style={{padding: 20}}> <a href="https://bj.ke.com/ershoufang/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >二手房</a> </Hidden> <Hidden visible={record.toFang} tag='p'> <a href="https://bj.fang.ke.com/loupan/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >新房</a> </Hidden> </li> </ul> </div> ) } export default App
简单就是封装Hidden组件,通过visible去控制是否渲染。
相信聪明的你一定知道怎么去封装Hidden
笔者刚开始是这么写的
import React, { Component } from 'react' export default class Hidden extends Component { render() { const { visible, children } = this.props const content = visible "text-align: center">原来的横着排列的元素,一下子竖着排列了。这可不太好,本来给我套个div,我都可以勉强接收,现在连我布局都给我变了。
怎么办?笔者突然想到使用vue-router中的router-link时,标签是可以通过tag去替换默认标签的。
那我们再给它个tag呗,连带自定义属性。
import React, { Component } from 'react' export default class Hidden extends Component { render() { const { visible, children, tag = 'div', ...rest } = this.props const content = visible "htmlcode">{ record.toFang && record.toKe && record.toSecondHand && <span> <a style={{padding: 20}} href="https://bj.ke.com" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >贝壳首页</a> <a style={{padding: 20}} href="https://bj.ke.com/ershoufang/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >二手房</a> <a style={{padding: 20}} href="https://bj.fang.ke.com/loupan/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >新房</a> </span> } <Hidden visible={record.toFang && record.toKe && record.toSecondHand} tag='span'> a href="https://bj.ke.com" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >贝壳首页</a> <a style={{padding: 20}} href="https://bj.ke.com/ershoufang/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >二手房</a> <a style={{padding: 20}} href="https://bj.fang.ke.com/loupan/" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >新房</a> </Hidden>其实感觉也没多大用处hhhh
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