React写关键字高亮的三个方案

1.js正则replaceAll+dangerouslySetInnerHTML={{ __html: xxx }}危险属性

步骤最简单,但是是危险属性,不推荐使用,项目中实在没有头绪,可以使用它应急

通过useMemo计算得到新的状态值,赋值给dangerouslySetInnerHTML属性的__html

关键代码:

const [state1, setState1] = useState('我爱中国,中国爱我')const updateState1 = useMemo(() => {return state1.replaceAll('中国', '<span style="color:red;">中国</span>')}, [state1])<div dangerouslySetInnerHTML={{ __html: updateState1 }}></div>

2.useMemo计算遍历后将关键字替换为React标签写法(内容为关键字),使用_.map渲染

(要不是replace不能转换为React标签,只支持字符串也不用这么麻烦)

关键代码:

const updateState2 = useMemo(() => {return highlightPassword(state2, '_.map_')}, [state2])function highlightPassword(str0: any, key_prefix?: string) {const password = '中国';const pattern = new RegExp(`\\B(?=((${password})+)+(?!(${password})))`, 'g')return str0.replace(pattern, '||||').split('||||').map((item, index) => {const idx = item.indexOf(password)return <span key={key_prefix + index}>{idx >= 0? <><span style={{ color: 'red' }}>{item.substring(0, password.length)}</span>{item.substring(password.length, item.length)}</>: item}</span>});}<p>map遍历children元素:</p>{_.map(updateState2, (child) => {return child})}

3.遍历后将关键字替换为React标签写法(内容为关键字),使用ReactDOM.render方法插入到指定元素中

关键代码:

const Test = () => {const [state2, setState2] = useState<any>('我爱中国,中国中国爱我')useEffect(() => {// 遍历将关键字换成react写法的标签,使用ReactDOM.render方法渲染到页面上const str = highlightPassword(state2, 'ReactDOM.render_')ReactDOM.render(<div>{str}</div>, document.getElementsByClassName('my-highlight-test')[0])}, [state2])function highlightPassword(str0: any, key_prefix?: string) {const password = '中国';const pattern = new RegExp(`\\B(?=((${password})+)+(?!(${password})))`, 'g')return str0.replace(pattern, '||||').split('||||').map((item, index) => {const idx = item.indexOf(password)return <span key={key_prefix + index}>{idx >= 0? <><span style={{ color: 'red' }}>{item.substring(0, password.length)}</span>{item.substring(password.length, item.length)}</>: item}</span>});}<p>ReactDOM.render方法:</p><div className="my-highlight-test"></div>

完整代码示例:

import React, { useEffect, useMemo, useState } from 'react'
import ReactDOM from 'react-dom';
import _ from 'lodash';const Test = () => {const [password,] = useState('中国')const [state1, setState1] = useState('我爱中国,中国爱我')const [state2, setState2] = useState<any>('我爱中国,中国中国爱我')useEffect(() => {// 遍历将关键字换成react写法的标签,使用ReactDOM.render方法渲染到页面上const str = highlightPassword(state2, 'ReactDOM.render_')ReactDOM.render(<div>{str}</div>, document.getElementsByClassName('my-highlight-test')[0])}, [state2])const updateState1 = useMemo(() => {return state1.replaceAll(password, str => `<span style="color:red;">${str}</span>`)}, [state1])const updateState2 = useMemo(() => {return highlightPassword(state2, '_.map_')}, [state2])useEffect(() => {setTimeout(() => {setState1('哈哈哈,中国万岁,万岁万万岁,中国加油!')setState2('哈哈哈,中国中国万岁,万岁万万岁,中国中国加油!爱你中国!')}, 2000)}, [])function highlightPassword(str0: any, key_prefix?: string) {const pattern = new RegExp(`\\B(?=((${password})+)+(?!(${password})))`, 'g')return str0.replace(pattern, '||||').split('||||').map((item, index) => {const idx = item.indexOf(password)return <span key={key_prefix + index}>{idx >= 0? <><span style={{ color: 'red' }}>{item.substring(0, password.length)}</span>{item.substring(password.length, item.length)}</>: item}</span>});}return (<div><p>dangerouslySetInnerHTML方式:</p><div dangerouslySetInnerHTML={{ __html: updateState1 }}></div><p>map遍历children元素:</p>{_.map(updateState2, (child) => {return child})}<p>ReactDOM.render方法:</p><div className="my-highlight-test"></div></div>)
}export default Test

显示效果：

初始化页面时：