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)

使用glob包，只需要添加一个斜杠来查找目录:

import {promise as glob} from "glob-promise"

const firstLevelFolders = await glob("MyFolder/*/")
const recursiveFolders = await glob("MyFolder/**/")

使用路径列出目录。

function getDirectories(path) {
  return fs.readdirSync(path).filter(function (file) {
    return fs.statSync(path+'/'+file).isDirectory();
  });
}

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)

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);
    });
});

完全异步的版本与ES6，只有本机包，fs。Promises和async/await，并行执行文件操作:

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

async function listDirectories(rootPath) {
    const fileNames = await fs.promises.readdir(rootPath);
    const filePaths = fileNames.map(fileName => path.join(rootPath, fileName));
    const filePathsAndIsDirectoryFlagsPromises = filePaths.map(async filePath => ({path: filePath, isDirectory: (await fs.promises.stat(filePath)).isDirectory()}))
    const filePathsAndIsDirectoryFlags = await Promise.all(filePathsAndIsDirectoryFlagsPromises);
    return filePathsAndIsDirectoryFlags.filter(filePathAndIsDirectoryFlag => filePathAndIsDirectoryFlag.isDirectory)
        .map(filePathAndIsDirectoryFlag => filePathAndIsDirectoryFlag.path);
}

经过测试，它工作得很好。