index.js

const DirectoryTree = require('directory-tree-md');
const PATH = require('path');
const UPATH = require('upath');
const write = require('write');
const FS = require('fs');

function getAllWatchPath(arr, pathArr = []) {
  arr.forEach((item) => {
    if (item.type === 'file') {
      pathArr.push(item.path)
    }
    if (item.children && item.children.length > 0) {
      pathArr.concat(getAllWatchPath(item.children, pathArr));
    }
  })
  return pathArr;
}

module.exports = class CopySpareWebpackPlugin {
  constructor(options) {
    this.option = options;
  }
  apply(compiler) {
    compiler.hooks.afterCompile.tapAsync(this.constructor.name, (compilation, callback) => {
      const { path, sep, directoryTrees } = this.option;
      const { dir, ...otherOtions } = directoryTrees;
      let fileItems = []
      if (Array.isArray(dir)) {
        fileItems = dir.map((filepath) => DirectoryTree(filepath, otherOtions));
      } else {
        fileItems = DirectoryTree(dir, otherOtions);
      }
      const filemds = getAllWatchPath(fileItems);
      filemds.forEach((filePathItem) => {
        const currentPath = UPATH.normalizeSafe(filePathItem);
        if (sep) {
          filePathItem = filePathItem.replace(process.cwd() + PATH.sep, '').replace(/\//g, sep);
          filePathItem = PATH.resolve(path, filePathItem);
        }
        if (!FS.existsSync(filePathItem)) {
          if (this.addDependency) this.addDependency(currentPath);
          let content = FS.readFileSync(currentPath);
          write.sync(filePathItem, content);
        }
      })
      callback()
    });
  }
}