kkbpack.js

#!  /usr/bin/env  node

const path = require('path') 
const fs = require('fs') 
const defaultConfig = {
  entry: "./src/index.js",
  output: {
    filename: 'bundle.js'
  }
}
const config = {
  ...defaultConfig,
  ...require(path.resolve('./kkbpack.config.js'))
}
//  console.log(config)

class KkbPack {
  constructor(config) {
    this.config = config
    // 入 口
    this.entry = config.entry
    // 工作路径
    this.root = process.cwd()
    // 依赖关系
    this.modules = {}
  }
  // 创建模块
  createModule(modulePath, name) {
    //  modulePath是绝对路径，获取文件
    // name是相对路径，作为key
    // let fileContent = fs.readFileSync(modulePath, 'utf-8')

    let fileContent = this.getCode(modulePath);
    // console.log('fileContent: ', fileContent);
    //  ./src/index.js  文件的父目录，其实就是src
    // 解析soruce源码
    const { code, deps } = this.parse(fileContent, path.dirname(name))
    console.log('code, deps: ', code, deps);
    //  this.modules[name]  =  code
    // console.log('name: ', name);
    this.modules[name] = `function(module,exports,__kkbpack_require__){ eval(\`${code}\`)}`
    // 递归获取依赖
    deps.forEach(dep => {
      this.createModule(path.join(this.root, dep), './' + dep)
    })
  }

  getCode (modulePath) {
    let content = fs.readFileSync(modulePath, 'utf-8')
    // this.config.module.rules.forEach(r => {
    //   if(r.test.test(modulePath)) {
    //     const loader = require(r.use[0])
    //     content = loader(content)
    //   }
    // })
    return content
  }
  
  parse(code, parent) {
    // console.log('code: ', code);
    let deps = []
    //  识别  require('xx')
    var r = /require\((.*)\)/g;
    code = code.replace(r, function (match, arg) {
      // console.log('arg: ', arg);
      //  console.log(1,match,  arg.replace(/'|"/g,''))
      const retPath = path.join(parent, arg.replace(/'|"/g, '')) 
      deps.push(retPath)
      return `__kkbpack_require__("./${retPath}")`
    })
    return {
      code,
      deps
    }
  }
  generateModuleStr() {
    //  生成model字符串
    let fnTemp = ""
    Object.keys(this.modules).forEach(name => {
      fnTemp += `"${name}":${this.modules[name]},`
    })
    console.log('fnTemp: ', fnTemp);
    return fnTemp
  }

  generateFile() {
    //  console.log(this.modules,  this.entry)
    //  console.log(123,this.root)
    let template = fs.readFileSync(path.resolve(__dirname, './template.js'), 'utf-8')

      template = template.replace('__entry__', this.entry)
      .replace('__content__', this.generateModuleStr()) 
      fs.writeFileSync('./dist/' + this.config.output.filename, template)
    }
    start() {
      // 创建模块依赖关系
      console.log('开始啦1')
      const entryPath = path.resolve(this.root, this.entry) 
      this.createModule(entryPath, this.entry) 
      this.generateFile()
    }

  }

  const kkb = new KkbPack(config) 
  kkb.start()

  console.log(' 	\n')