webpack文件夹资源替换插件

使用：输入文件夹路径数组

const path = require("path");
function resolve(dir) {
  return path.join(__dirname, "..", dir);
}

//demo
plugins: [
    new AliasDirReplacementPlugin([resolve('www'),resolve('src')]),

　　

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
"use strict";

const path = require("path");
const fs = require("fs");

function findFileIndex(filepath,aliasDirs,extensions) {
  const resource=filepath.replace(/\?.+/,'')
  //是否存在后缀
  let hasExt=-1;
  for(let i=0;i<extensions.length;i++){
    if(resource.indexOf(extensions[i])+extensions[i].length===resource.length){
      hasExt=i;
      break;
    }
  }
  //找到匹配得
  let index=-1;
  for(let i=0;i<aliasDirs.length;i++){
    const dirPath=aliasDirs[i];
    if(resource.indexOf(dirPath)===0){
      index=i
      break;
    }
  }

  const resourceArr=[]
  for(let i=0;i<aliasDirs.length;i++){
    const dirPath=aliasDirs[i];
    if(index===i){
      resourceArr.push(resource)
    }else{
      resourceArr.push(resource.replace(aliasDirs[index],dirPath))
    }
  }

  let nIndex=-1;
  for(let i=0;i<resourceArr.length;i++){
    const nResource=resourceArr[i];
    if(fs.existsSync(nResource)){
      nIndex=i;
      break;
    }
    if(hasExt===-1){
      let fit=false;
      for(let j=0;j<extensions.length;j++){
        if(fs.existsSync(nResource+extensions[j])){
          fit=true
          break;
        }
      }
      if(fit){
        nIndex=i;
        break;
      }
    }
  }
  return [index,nIndex]
}
/*别名文件夹替换插件
用于马甲包开发
* */
class AliasDirReplacementPlugin {
  constructor(aliasDirs) {
    this.aliasDirs=aliasDirs;
  }
  apply(compiler) {
    const aliasDirs = this.aliasDirs;
    const extensions=compiler.options.resolve.extensions
    const alias=compiler.options.resolve.alias
    compiler.hooks.normalModuleFactory.tap(
      "AliasDirReplacementPlugin",
      nmf => {
        nmf.hooks.beforeResolve.tap("AliasDirReplacementPlugin", result => {
          if (!result) return;

          if(/node_modules/.test(result.context)||/node_modules/.test(result.request)){
            return result;
          }
          const request=result.request.replace(/\?.+/,'');

          let isAlias=''
          //解析别名
          for(let key in alias){
            if(result.request.indexOf(key)===0){
              isAlias=key;
              break;
            }
          }
          //如果是别名解析
          if(isAlias){
            const filepath=result.request.replace(isAlias,alias[isAlias]);
            const [index,nIndex]=findFileIndex(filepath,aliasDirs,extensions)

            if(nIndex>-1){
              result.request=filepath.replace(aliasDirs[index],aliasDirs[nIndex]);
            }
            return result;
          }
          if(/^(\.\/|\.\.\/)/.test(request)){
            const [index,nIndex]=findFileIndex(path.join(result.context,request),aliasDirs,extensions)
            if(nIndex!==index){
              result.context=result.context.replace(aliasDirs[index],aliasDirs[nIndex]);
            }
          }
          return result;
        });
      }
    );
  }
}

module.exports = AliasDirReplacementPlugin;