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

使用承诺(Q)以函数式风格解决此问题:

var fs = require('fs'),
    fsPath = require('path'),
    Q = require('q');

var walk = function (dir) {
  return Q.ninvoke(fs, 'readdir', dir).then(function (files) {

    return Q.all(files.map(function (file) {

      file = fsPath.join(dir, file);
      return Q.ninvoke(fs, 'lstat', file).then(function (stat) {

        if (stat.isDirectory()) {
          return walk(file);
        } else {
          return [file];
        }
      });
    }));
  }).then(function (files) {
    return files.reduce(function (pre, cur) {
      return pre.concat(cur);
    });
  });
};

它返回一个数组的promise,所以你可以这样使用它:

walk('/home/mypath').then(function (files) { console.log(files); });

其他回答

香草ES6 +异步/等待+小和可读

我没有在这篇文章中找到我想要的答案;在不同的答案中有一些相似的元素,但我只想要一些简单易读的东西。

为了防止它在未来帮助到任何人(比如几个月后的我自己),这就是我最终使用的:

const { readdir } = require('fs/promises');
const { join } = require('path');

const readdirRecursive = async dir => {
  const files = await readdir( dir, { withFileTypes: true } );

  const paths = files.map( async file => {
    const path = join( dir, file.name );

    if ( file.isDirectory() ) return await readdirRecursive( path );

    return path;
  } );

  return ( await Promise.all( paths ) ).flat( Infinity );
}

module.exports = {
  readdirRecursive,
}

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/

为了好玩,这里有一个基于流的版本,它与highland.js streams库一起工作。作者之一是维克多·伍。

###
  directory >---m------> dirFilesStream >---------o----> out
                |                                 |
                |                                 |
                +--------< returnPipe <-----------+

  legend: (m)erge  (o)bserve

 + directory         has the initial file
 + dirListStream     does a directory listing
 + out               prints out the full path of the file
 + returnPipe        runs stat and filters on directories

###

_ = require('highland')
fs = require('fs')
fsPath = require('path')

directory = _(['someDirectory'])
mergePoint = _()
dirFilesStream = mergePoint.merge().flatMap((parentPath) ->
  _.wrapCallback(fs.readdir)(parentPath).sequence().map (path) ->
    fsPath.join parentPath, path
)
out = dirFilesStream
# Create the return pipe
returnPipe = dirFilesStream.observe().flatFilter((path) ->
  _.wrapCallback(fs.stat)(path).map (v) ->
    v.isDirectory()
)
# Connect up the merge point now that we have all of our streams.
mergePoint.write directory
mergePoint.write returnPipe
mergePoint.end()
# Release backpressure.  This will print files as they are discovered
out.each H.log
# Another way would be to queue them all up and then print them all out at once.
# out.toArray((files)-> console.log(files))

使用承诺(Q)以函数式风格解决此问题:

var fs = require('fs'),
    fsPath = require('path'),
    Q = require('q');

var walk = function (dir) {
  return Q.ninvoke(fs, 'readdir', dir).then(function (files) {

    return Q.all(files.map(function (file) {

      file = fsPath.join(dir, file);
      return Q.ninvoke(fs, 'lstat', file).then(function (stat) {

        if (stat.isDirectory()) {
          return walk(file);
        } else {
          return [file];
        }
      });
    }));
  }).then(function (files) {
    return files.reduce(function (pre, cur) {
      return pre.concat(cur);
    });
  });
};

它返回一个数组的promise,所以你可以这样使用它:

walk('/home/mypath').then(function (files) { console.log(files); });

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。