如果需要使用全异步版本。你可以有这样的东西。

记录目录长度，使用它作为一个指示器，以告知是否所有异步统计任务已完成。 如果异步统计任务已完成，则所有文件统计都已检查，因此调用回调

这将只在Node.js是单线程的情况下工作，因为它假设没有两个异步任务会同时增加计数器。

'use strict';

var fs = require("fs");
var path = require("path");
var basePath = "./";

function result_callback(results) {
    results.forEach((obj) => {
        console.log("isFile: " + obj.fileName);
        console.log("fileName: " + obj.isFile);
    });
};

fs.readdir(basePath, (err, files) => {
    var results = [];
    var total = files.length;
    var finished = 0;

    files.forEach((fileName) => {
        // console.log(fileName);
        var fullPath = path.join(basePath, fileName);

        fs.stat(fullPath, (err, stat) => {
            // this will work because Node.js is single thread
            // therefore, the counter will not increment at the same time by two callback
            finished++;

            if (stat.isFile()) {
                results.push({
                    fileName: fileName,
                    isFile: stat.isFile()
                });
            }

            if (finished == total) {
                result_callback(results);
            }
        });
    });
});

正如您所看到的，这是一种“深度优先”的方法，这可能会导致回调地狱，而且它不是完全“功能性的”。人们试图用Promise来解决这个问题，方法是将异步任务包装到Promise对象中。

'use strict';

var fs = require("fs");
var path = require("path");
var basePath = "./";

function result_callback(results) {
    results.forEach((obj) => {
        console.log("isFile: " + obj.fileName);
        console.log("fileName: " + obj.isFile);
    });
};

fs.readdir(basePath, (err, files) => {
    var results = [];
    var total = files.length;
    var finished = 0;

    var promises = files.map((fileName) => {
        // console.log(fileName);
        var fullPath = path.join(basePath, fileName);

        return new Promise((resolve, reject) => {
            // try to replace fullPath wil "aaa", it will reject
            fs.stat(fullPath, (err, stat) => {
                if (err) {
                    reject(err);
                    return;
                }

                var obj = {
                    fileName: fileName,
                    isFile: stat.isFile()
                };

                resolve(obj);
            });
        });
    });

    Promise.all(promises).then((values) => {
        console.log("All the promise resolved");
        console.log(values);
        console.log("Filter out folder: ");
        values
            .filter((obj) => obj.isFile)
            .forEach((obj) => {
                console.log(obj.fileName);
            });
    }, (reason) => {
        console.log("Not all the promise resolved");
        console.log(reason);
    });
});

承诺

import { readdir } from 'fs/promises'

const getDirectories = async source =>
  (await readdir(source, { withFileTypes: true }))
    .filter(dirent => dirent.isDirectory())
    .map(dirent => dirent.name)

回调

import { readdir } from 'fs'

const getDirectories = (source, callback) =>
  readdir(source, { withFileTypes: true }, (err, files) => {
    if (err) {
      callback(err)
    } else {
      callback(
        files
          .filter(dirent => dirent.isDirectory())
          .map(dirent => dirent.name)
      )
    }
  })

Syncronous

import { readdirSync } from 'fs'

const getDirectories = source =>
  readdirSync(source, { withFileTypes: true })
    .filter(dirent => dirent.isDirectory())
    .map(dirent => dirent.name)

或者，如果您能够使用外部库，您可以使用filehound。它支持回调，承诺和同步调用。

使用承诺:

const Filehound = require('filehound');

Filehound.create()
  .path("MyFolder")
  .directory() // only search for directories
  .find()
  .then((subdirectories) => {
    console.log(subdirectories);
  });

使用回调函数:

const Filehound = require('filehound');

Filehound.create()
  .path("MyFolder")
  .directory()
  .find((err, subdirectories) => {
    if (err) return console.error(err);

    console.log(subdirectories);
  });

同步调用:

const Filehound = require('filehound');

const subdirectories = Filehound.create()
  .path("MyFolder")
  .directory()
  .findSync();

console.log(subdirectories);

欲了解更多信息(和示例)，请查看文档:https://github.com/nspragg/filehound

声明:我是作者。

对于getDirectories的异步版本，你需要async模块:

var fs = require('fs');
var path = require('path');
var async = require('async'); // https://github.com/caolan/async

// Original function
function getDirsSync(srcpath) {
  return fs.readdirSync(srcpath).filter(function(file) {
    return fs.statSync(path.join(srcpath, file)).isDirectory();
  });
}

function getDirs(srcpath, cb) {
  fs.readdir(srcpath, function (err, files) {
    if(err) { 
      console.error(err);
      return cb([]);
    }
    var iterator = function (file, cb)  {
      fs.stat(path.join(srcpath, file), function (err, stats) {
        if(err) { 
          console.error(err);
          return cb(false);
        }
        cb(stats.isDirectory());
      })
    }
    async.filter(files, iterator, cb);
  });
}

这应该做到:

CoffeeScript(同步)

fs = require 'fs'

getDirs = (rootDir) ->
    files = fs.readdirSync(rootDir)
    dirs = []

    for file in files
        if file[0] != '.'
            filePath = "#{rootDir}/#{file}"
            stat = fs.statSync(filePath)

            if stat.isDirectory()
                dirs.push(file)

    return dirs

CoffeeScript(异步)

fs = require 'fs'

getDirs = (rootDir, cb) ->
    fs.readdir rootDir, (err, files) ->
        dirs = []

        for file, index in files
            if file[0] != '.'
                filePath = "#{rootDir}/#{file}"
                fs.stat filePath, (err, stat) ->
                    if stat.isDirectory()
                        dirs.push(file)
                    if files.length == (index + 1)
                        cb(dirs)

JavaScript(异步)

var fs = require('fs');
var getDirs = function(rootDir, cb) { 
    fs.readdir(rootDir, function(err, files) { 
        var dirs = []; 
        for (var index = 0; index < files.length; ++index) { 
            var file = files[index]; 
            if (file[0] !== '.') { 
                var filePath = rootDir + '/' + file; 
                fs.stat(filePath, function(err, stat) {
                    if (stat.isDirectory()) { 
                        dirs.push(this.file); 
                    } 
                    if (files.length === (this.index + 1)) { 
                        return cb(dirs); 
                    } 
                }.bind({index: index, file: file})); 
            }
        }
    });
}

这个答案不使用像readdirSync或statSync这样的阻塞函数。它不使用外部依赖关系，也不陷入回调地狱的深渊。

相反，我们使用现代JavaScript的便利，如Promises和async-await语法。异步结果是并行处理的;〇不是按顺序

const { readdir, stat } =
  require ("fs") .promises

const { join } =
  require ("path")

const dirs = async (path = ".") =>
  (await stat (path)) .isDirectory ()
    ? Promise
        .all
          ( (await readdir (path))
              .map (p => dirs (join (path, p)))
          )
        .then
          ( results =>
              [] .concat (path, ...results)
          )
    : []

我将安装一个示例包，然后测试我们的函数-

$ npm install ramda
$ node

让我们看看它是如何工作的

> dirs (".") .then (console.log, console.error)

[ '.'
, 'node_modules'
, 'node_modules/ramda'
, 'node_modules/ramda/dist'
, 'node_modules/ramda/es'
, 'node_modules/ramda/es/internal'
, 'node_modules/ramda/src'
, 'node_modules/ramda/src/internal'
]

使用一个通用模块Parallel，我们可以简化dirs -的定义

const Parallel =
  require ("./Parallel")

const dirs = async (path = ".") =>
  (await stat (path)) .isDirectory ()
    ? Parallel (readdir (path))
        .flatMap (f => dirs (join (path, f)))
        .then (results => [ path, ...results ])
    : []

上面使用的Parallel模块是从一组旨在解决类似问题的函数中提取出来的模式。更多解释请参见相关问答。