使用nodejs分离html文件里的js和css详解

摘要： 本文要实现的内容，使用nodejs 对文件的增删改查，演示的例子-》分离出一个html 文件里面的script 和style 里面的内容，然后单独生成js文件和css 文件。中间处理异步的api-》async/await , Promise

项目托管：extract-js-css , 欢迎star

直接上代码：

// extract-js-css// import fs from 'fs'var fs = require('fs')// import csscomb from 'csscomb'// var csscomb = require('csscomb')// var comb = new csscomb('zen');// console.log(comb) // 删除文件const deleteFile = (path)=>{  return new Promise(resolve => {    fs.unlink(path, (err) => {      if (err) {        console.log(err)        return      };      console.log(`已成功删除 ${path}文件`);      resolve()    });  })} // 删除文件夹const deleteDir = async (path)=>{  let _files = await new Promise (resolve => {    fs.readdir(path, (err,files) => {      if (err) {        console.log(err)      };      console.log(`已成功读取 ${path} 文件夹`);      resolve(files)    })  })   if(_files && _files.length) {    for(let i =0;i<_files.length;i++) {      // console.log(_files[i],'innnnnn')      await deleteFile('./test/'+ _files[i])    }  }  // console.log('delete hou')   await new Promise(resolve => {    fs.rmdir(path, (err) => {      if (err) {        console.log(err)      };      console.log(`已成功删除空 ${path}文件夹`);      resolve()    })  });}const emptyDir = (path) => {  return new Promise(resolve => {    fs.rmdir(path, (err) => {      if (err) {        console.log(err)      };      console.log(`已成功删除空 ${path}文件夹`);      resolve()    })  })}// 新建文件夹/** *  */const mkdirTest = ()=>{  return new Promise(resolve => {    fs.mkdir('./test', { recursive: true }, (err, data)=>{      if (err) {        console.log(err)      };      console.log('新建文件夹成功')      resolve()    })  })} // 读取html 内容/** *  */const readHtml = ()=>{  return new Promise(resolve => {    fs.readFile('./test.html', 'utf-8', (err, data)=>{      if(err) {        throw Error(err)      }      console.log('test.html 读取成功！--NO1')      resolve(data)    })  })} // 写入css 和js/** * 向文件中追加内容 * @param {是文件名字} path  * @param {写入文件的内容} data  * @param {文件类型} type  * @author erlinger * @time  */const appendFile = (path, data, type) => {  return new Promise(resolve => {    fs.appendFile(path, data, (err) => {      if (err) {        console.log(err)      };      console.log(`${type}数据已追加到文件`);      resolve()    });  })}// 写一个htmlconst writeHtml = (path, data) => {  return new Promise(resolve => {    fs.writeFile(path, data, (err) =>{      if(err) {        console.log('err', err)        return      }      console.log(`${path} 写入成功，功能结束!`);      resolve() // 必须resolve 。不然 promise 就到此为止，调用该方法后面的代码将不执行    })  })} // 插件 方法入口(async ()=>{  console.log('==========================game-start=============================');  await deleteDir('./test');  console.log('我应该是等---删除文件夹后---才出现')   await mkdirTest();  console.log('我应该是在---文件夹新建成功---后出现！');   let cssReg = /<style>[/s|/S]*?<//style>/ig;  let jsReg = /<script>[/s|/S]*?<//script>/ig;  let allStyleReg = /<//style>[/s|/S]*?<style>/ig;  let allScriptReg = /<//script>[/s|/S]*?<script>/ig;  let cssLink = '<link rel="stylesheet" href="./test.css" rel="external nofollow" >';  let jsrc = '<script src="./test.js"></script>';  let styleCollection, scriptColletion;  let cssContent = '', jsContent = '', htmlContentStr = '';   let originContent = await readHtml();  styleCollection = originContent.match(cssReg);  scriptColletion = originContent.match(jsReg);     // 处理 css  for (let i =0;i<styleCollection.length;i++) {    cssContent += JSON.stringify(styleCollection[i]);  }   cssContent = cssContent.replace(/<style>/g,'').replace(/<//style>/g, '').replace(/("")/g,'')     for (let i =0;i<scriptColletion.length;i++) {    jsContent += JSON.stringify(scriptColletion[i]);  }     jsContent = jsContent.replace(/<script>/g,'').replace(/<//script>/g, '')  .replace(/<//script>"*<script>/g, '').replace(/("")/g,'')     await appendFile('./test/test.css', JSON.parse(cssContent), 'css');  console.log('我应该是在---css写入成功---后出现！');   await appendFile('./test/test.js', JSON.parse(jsContent), 'js');  console.log('我应该是在---js写入成功---后出现！');   htmlContentStr = originContent  .replace(allStyleReg, '')  .replace(cssReg, cssLink)  .replace(allScriptReg, '')  .replace(jsReg, jsrc);  console.log('copyTest.html 文本已经格式化，准备写入');  await writeHtml('./test/copyTest.html', htmlContentStr);   console.log('==========================game-over=============================');})()