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);
    });
});

函数式编程

const fs = require('fs')
const path = require('path')
const R = require('ramda')

const getDirectories = pathName => {
    const isDirectory = pathName => fs.lstatSync(pathName).isDirectory()
    const mapDirectories = pathName => R.map(name => path.join(pathName, name), fs.readdirSync(pathName))
    const filterDirectories = listPaths => R.filter(isDirectory, listPaths)

    return {
        paths:R.pipe(mapDirectories)(pathName),
        pathsFiltered: R.pipe(mapDirectories, filterDirectories)(pathName)
    }
}

使用node.js版本>= v10.13.0, fs. js。readdirSync将返回一个fs数组。如果withFileTypes选项设置为true，则直接对象。

所以你可以用，

const fs = require('fs')

const directories = source => fs.readdirSync(source, {
   withFileTypes: true
}).reduce((a, c) => {
   c.isDirectory() && a.push(c.name)
   return a
}, [])

另一种递归方法

感谢Mayur了解我的withFileTypes。我写了下面的代码来递归地获取特定文件夹的文件。可以很容易地修改它以只获取目录。

const getFiles = (dir, base = '') => readdirSync(dir, {withFileTypes: true}).reduce((files, file) => {
    const filePath = path.join(dir, file.name)
    const relativePath = path.join(base, file.name)
    if(file.isDirectory()) {
        return files.concat(getFiles(filePath, relativePath))
    } else if(file.isFile()) {
        file.__fullPath = filePath
        file.__relateivePath = relativePath
        return files.concat(file)
    }
}, [])

 var getDirectories = (rootdir , cb) => {
    fs.readdir(rootdir, (err, files) => {
        if(err) throw err ;
        var dirs = files.map(filename => path.join(rootdir,filename)).filter( pathname => fs.statSync(pathname).isDirectory());
        return cb(dirs);
    })

 }
 getDirectories( myDirectories => console.log(myDirectories));``

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。