关于使用fs.readdir进行异步目录搜索有什么想法吗?我意识到我们可以引入递归,并调用read目录函数来读取下一个目录,但我有点担心它不是异步的…

什么好主意吗?我已经看了node-walk,它很棒,但它不能像readdir那样只给我数组中的文件。虽然

寻找这样的输出…

['file1.txt', 'file2.txt', 'dir/file3.txt']

当前回答

使用async/await,这应该工作:

const FS = require('fs');
const readDir = promisify(FS.readdir);
const fileStat = promisify(FS.stat);

async function getFiles(dir) {
    let files = await readDir(dir);

    let result = files.map(file => {
        let path = Path.join(dir,file);
        return fileStat(path).then(stat => stat.isDirectory() ? getFiles(path) : path);
    });

    return flatten(await Promise.all(result));
}

function flatten(arr) {
    return Array.prototype.concat(...arr);
}

你可以用蓝鸟。许诺或许诺:

/**
 * Returns a function that will wrap the given `nodeFunction`. Instead of taking a callback, the returned function will return a promise whose fate is decided by the callback behavior of the given node function. The node function should conform to node.js convention of accepting a callback as last argument and calling that callback with error as the first argument and success value on the second argument.
 *
 * @param {Function} nodeFunction
 * @returns {Function}
 */
module.exports = function promisify(nodeFunction) {
    return function(...args) {
        return new Promise((resolve, reject) => {
            nodeFunction.call(this, ...args, (err, data) => {
                if(err) {
                    reject(err);
                } else {
                    resolve(data);
                }
            })
        });
    };
};

Node 8+内置了Promisify

请参阅我对生成器方法的其他回答,它可以更快地得到结果。

其他回答

短小、现代、高效:

import {readdir} from 'node:fs/promises'
import {join} from 'node:path'

const deepReadDir = async (dirPath) => await Promise.all(
  (await readdir(dirPath, {withFileTypes: true})).map(async (dirent) => {
    const path = join(dirPath, dirent.name)
    return dirent.isDirectory() ? await deepReadDir(path) : path
  }),
)

特别感谢函数提示使用{withFileTypes: true}。


这将自动将每个嵌套路径折叠成一个新的嵌套数组。例如,如果:

await deepReadDir('src')

返回如下内容:

[
  [
    'src/client/api.js',
    'src/client/http-constants.js',
    'src/client/index.html',
    'src/client/index.js',
    [ 'src/client/res/favicon.ico' ],
    'src/client/storage.js'
  ],
  [ 'src/crypto/keygen.js' ],
  'src/discover.js',
  [
    'src/mutations/createNewMutation.js',
    'src/mutations/newAccount.js',
    'src/mutations/transferCredit.js',
    'src/mutations/updateApp.js'
  ],
  [
    'src/server/authentication.js',
    'src/server/handlers.js',
    'src/server/quick-response.js',
    'src/server/server.js',
    'src/server/static-resources.js'
  ],
  [ 'src/util/prompt.js', 'src/util/safeWriteFile.js' ],
  'src/util.js'
]

但如果你想,你可以很容易地把它压平:

(await deepReadDir('src')).flat(Number.POSITIVE_INFINITY)
[
  'src/client/api.js',
  'src/client/http-constants.js',
  'src/client/index.html',
  'src/client/index.js',
  'src/client/res/favicon.ico',
  'src/client/storage.js',
  'src/crypto/keygen.js',
  'src/discover.js',
  'src/mutations/createNewMutation.js',
  'src/mutations/newAccount.js',
  'src/mutations/transferCredit.js',
  'src/mutations/updateApp.js',
  'src/server/authentication.js',
  'src/server/handlers.js',
  'src/server/quick-response.js',
  'src/server/server.js',
  'src/server/static-resources.js',
  'src/util/prompt.js',
  'src/util/safeWriteFile.js',
  'src/util.js'
]

另一个答案,但这次使用的是TypeScript:

/** * Recursively walk a directory asynchronously and obtain all file names (with full path). * * @param dir Folder name you want to recursively process * @param done Callback function, returns all files with full path. * @param filter Optional filter to specify which files to include, * e.g. for json files: (f: string) => /.json$/.test(f) */ const walk = ( dir: string, done: (err: Error | null, results ? : string[]) => void, filter ? : (f: string) => boolean ) => { let results: string[] = []; fs.readdir(dir, (err: Error, list: string[]) => { if (err) { return done(err); } let pending = list.length; if (!pending) { return done(null, results); } list.forEach((file: string) => { file = path.resolve(dir, file); fs.stat(file, (err2, stat) => { if (stat && stat.isDirectory()) { walk(file, (err3, res) => { if (res) { results = results.concat(res); } if (!--pending) { done(null, results); } }, filter); } else { if (typeof filter === 'undefined' || (filter && filter(file))) { results.push(file); } if (!--pending) { done(null, results); } } }); }); }); };

它使用了节点8中最多的新功能,包括Promises、util/promisify、destructuring、async-await、map+reduce等等,让你的同事在试图弄清楚发生了什么时挠头。

节点 8+

没有外部依赖。

const { promisify } = require('util');
const { resolve } = require('path');
const fs = require('fs');
const readdir = promisify(fs.readdir);
const stat = promisify(fs.stat);

async function getFiles(dir) {
  const subdirs = await readdir(dir);
  const files = await Promise.all(subdirs.map(async (subdir) => {
    const res = resolve(dir, subdir);
    return (await stat(res)).isDirectory() ? getFiles(res) : res;
  }));
  return files.reduce((a, f) => a.concat(f), []);
}

使用

getFiles(__dirname)
  .then(files => console.log(files))
  .catch(e => console.error(e));

节点 10.10+

更新到节点10+,甚至更多的whizbang:

const { resolve } = require('path');
const { readdir } = require('fs').promises;

async function getFiles(dir) {
  const dirents = await readdir(dir, { withFileTypes: true });
  const files = await Promise.all(dirents.map((dirent) => {
    const res = resolve(dir, dirent.name);
    return dirent.isDirectory() ? getFiles(res) : res;
  }));
  return Array.prototype.concat(...files);
}

请注意,从节点11.15.0开始,您可以使用files.flat()而不是array. prototype.concat(…files)来扁平化files数组。

11 +节点

如果你想让所有人都大吃一惊,你可以使用下面使用异步迭代器的版本。除了非常酷之外,它还允许使用者每次提取一个结果,这使得它更适合于真正大的目录。

const { resolve } = require('path');
const { readdir } = require('fs').promises;

async function* getFiles(dir) {
  const dirents = await readdir(dir, { withFileTypes: true });
  for (const dirent of dirents) {
    const res = resolve(dir, dirent.name);
    if (dirent.isDirectory()) {
      yield* getFiles(res);
    } else {
      yield res;
    }
  }
}

用法发生了变化,因为返回类型现在是异步迭代器而不是promise

;(async () => {
  for await (const f of getFiles('.')) {
    console.log(f);
  }
})()

如果有人感兴趣,我在这里写了更多关于异步迭代器的文章:https://qwtel.com/posts/software/async-generators-in-the-wild/

对于Node 10.3+,这里是一个For -await解决方案:

#!/usr/bin/env node

const FS = require('fs');
const Util = require('util');
const readDir = Util.promisify(FS.readdir);
const Path = require('path');

async function* readDirR(path) {
    const entries = await readDir(path,{withFileTypes:true});
    for(let entry of entries) {
        const fullPath = Path.join(path,entry.name);
        if(entry.isDirectory()) {
            yield* readDirR(fullPath);
        } else {
            yield fullPath;
        }
    }
}

async function main() {
    const start = process.hrtime.bigint();
    for await(const file of readDirR('/mnt/home/media/Unsorted')) {
        console.log(file);
    }
    console.log((process.hrtime.bigint()-start)/1000000n);
}

main().catch(err => {
    console.error(err);
});

这种解决方案的好处是,您可以立即开始处理结果;例如,读取媒体目录中的所有文件需要12秒,但如果我这样做,我可以在几毫秒内得到第一个结果。

现代基于promise的读dir递归版本:

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

const readDirRecursive = async (filePath) => {
    const dir = await fs.promises.readdir(filePath);
    const files = await Promise.all(dir.map(async relativePath => {
        const absolutePath = path.join(filePath, relativePath);
        const stat = await fs.promises.lstat(absolutePath);

        return stat.isDirectory() ? readDirRecursive(absolutePath) : absolutePath;
    }));

    return files.flat();
}