NodeJS递归列出目录中的文件

Question

I am trying to list all files in a directory (and files within any subdirectories) with the following code:

var fs = require('fs')

var walk = function(directoryName) {
  fs.readdir(directoryName, function(e, files) {
    files.forEach(function(file) {
      fs.stat(file, function(e, f) {
        if (f.isDirectory()) {
          walk(file)
        } else {
          console.log('- ' + file)
        }
      })
    })
  })
}

walk(__dirname)

However, when my code attempts to invoke walk(file) on line 8 I get the following error:

TypeError: Cannot call method 'isDirectory' of undefined
    at program.js:7:15
    at Object.oncomplete (fs.js:107:15)

Why is f undefined? If I have the directory structure below, shouldn't the code identify aaa.txt and bbb.txt as files, my_dir as a directory at which point it recursively calls walk and begins the process again (with zzz.txt being the value of f)?

- aaa.txt
- bbb.txt
+ my_dir
    - zzz.txt

Answer 1

Function fs.readdir lists the simple file names in that directory, not their absolute path. This is why the program failed to find them, thus leading to an error in fs.stat .

Here's the solution: concatenate the directory path name to the file.

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

var walk = function(directoryName) {
  fs.readdir(directoryName, function(e, files) {
    if (e) {
      console.log('Error: ', e);
      return;
    }
    files.forEach(function(file) {
      var fullPath = path.join(directoryName,file);
      fs.stat(fullPath, function(e, f) {
        if (e) {
          console.log('Error: ', e);
          return;
        }
        if (f.isDirectory()) {
          walk(fullPath);
        } else {
          console.log('- ' + fullPath);
        }
      });
    });
  });
};

Answer 2

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

var walk = function(directoryName) {

  fs.readdir(directoryName, function(e, files) {
    files.forEach(function(file) {
      fs.stat(directoryName + path.sep + file, function(e, f) {

        if (f.isDirectory()) {
          walk(directoryName + path.sep + file)
        } else {
          console.log(' - ' + file)
        }
      })
    })
  })
}

walk(__dirname)

Answer 3

Here's a version for async/await:

const { promises: fs } = require("fs");
const path = require("path");

async function walk(dir) {
    const entries = await fs.readdir(dir);
    let ret = [];
    for (const entry of entries) {
        const fullpath = path.resolve(dir, entry);
        const info = await fs.stat(fullpath);
        if (info.isDirectory()) {
            ret = [...ret, ...(await walk(fullpath))];
        } else {
            ret = [...ret, fullpath];
        }
    }
    return ret;
}

(async function () {
    console.log(await walk("/path/to/some/dir"));
})();

Answer 4

A fully synchronous version, for those situations where you cannot use async:

const walk = (dir, files = []) => {
    const dirFiles = fs.readdirSync(dir)
    for (const f of dirFiles) {
        const stat = fs.lstatSync(dir + path.sep + f)
        if (stat.isDirectory()) {
            walk(dir + path.sep + f, files)
        } else {
            files.push(dir + path.sep + f)
        }
    }
    return files
}
const allFiles = walk(someDir)