CodeMirror实现代码对比功能(插件react vue)

时间：2022-11-13 10:13:58|栏目：JavaScript代码|点击：次

要实现一个需求：一个代码编辑器，用户上次写的代码和现在的代码要区分出不同。网上找了几个案例，拿过去一用差点气吐血，报错像雪花一样，浪费时间！

本文中的代码，一键粘贴拿来即用，代码就是我在写这篇文章时写的demo，绝无报错。

1.第一步：下载插件

vue或者react都需要这一步且同样的下载方式。

npm install diff-match-patch save
npm install codemirror save
用yarn的话 npm install 替换成 yarn add …

2.vue代码如下：

建一个空白.vue文件然后一键复制以下代码：

<template>
  <div ref="codeMirror" class="code-contrast" style="width:100%;height:100%" />
</template>
 
<script>
import CodeMirror from 'codemirror'
import 'codemirror/lib/codemirror.css'
import 'codemirror/addon/merge/merge.js'
import 'codemirror/addon/merge/merge.css'
import DiffMatchPatch from 'diff-match-patch'
window.diff_match_patch = DiffMatchPatch
window.DIFF_DELETE = -1
window.DIFF_INSERT = 1
window.DIFF_EQUAL = 0
 
export default {
  name: 'CodeMirror',
 
  data() {
    return {
      oldValue: '我们到现在还是一样的',
      newValue: '我们到现在还是一样的，这几个字给我标个红吧！',
      isReadOnly: false
    }
  },
  watch: {
    oldValue: {
      immediate: true,
      handler() {
        this.$nextTick(() => {
          this.initUI()
        })
      }
    },
    newValue: {
      immediate: true,
      handler() {
        this.$nextTick(() => {
          this.initUI()
        })
      }
    }
  },
  methods: {
    initUI() {
      if (this.newValue == null) return
      const target = this.$refs.codeMirror
      target.innerHTML = ''
      CodeMirror.MergeView(target, {
        value: this.oldValue, // 上次内容
        origLeft: null,
        orig: this.newValue, // 本次内容
        lineNumbers: true, // 显示行号
        mode: 'text/html',
        highlightDifferences: true,
        connect: 'align',
        readOnly: this.isReadOnly // 只读 不可修改
      })
    }
  }
}
</script>
<style lang="scss">
.code-contrast .CodeMirror-merge-copy,
  .CodeMirror-merge-scrolllock-wrap {
 
    display: none !important;
 
}
</style>

效果图：

细节处对比：

3.react hooks代码如下：

记得先下载第一步的文件然后再一键复制。

对比效果图如下：

import React, { useEffect, useState, useRef } from 'react'
import CodeMirror from 'codemirror'
import 'codemirror/lib/codemirror.css'
import 'codemirror/addon/merge/merge.js'
import 'codemirror/addon/merge/merge.css'
import DiffMatchPatch from 'diff-match-patch'
export default function Demo () {
  window.diff_match_patch = DiffMatchPatch
  window.DIFF_DELETE = -1
  window.DIFF_INSERT = 1
  window.DIFF_EQUAL = 0
  const [num, setNum] = useState(10)
  const [oldValue, setOldValue] = useState('11111111111')
  const [newValue, setNewValue] = useState('11111111112222222222')
  const [isReadOnly, setIsReadOnly] = useState(false)
 
  const codeMirror = useRef(null)
  const initUI = () => {
    if (newValue == null) return
    const target = codeMirror.current
    console.log(target, '00000000000')
    target.innerHTML = ''
    CodeMirror.MergeView(target, {
      value: oldValue, // 上次内容
      origLeft: null,
      orig: newValue, // 本次内容
      lineNumbers: true, // 显示行号
      mode: 'text/html',
      highlightDifferences: true,
      connect: 'align',
      readOnly: isReadOnly // 只读 不可修改
    })
  }
  useEffect(() => {
    initUI()
  }, [newValue])
  useEffect(() => {
    initUI()
  }, [oldValue])
  return (
    <div>
      <div ref={codeMirror} className="code-contrast" style={{ width: '100%', height: '100%' }}></div>
    </div>
  )
}