readdir-enhanced

Enhanced fs.readdir()

readdir-enhanced is a backward-compatible drop-in replacement for fs.readdir() and fs.readdirSync() with tons of extra features (filtering, recursion, absolute paths, stats, and more) as well as additional APIs for Promises, Streams, and EventEmitters.

Pick Your API

readdir-enhanced has multiple APIs, so you can pick whichever one you prefer. There are three main APIs:

• Synchronous API
  aliases: readdir.sync, readdir.readdirSync
  Blocks the thread until all directory contents are read, and then returns all the results.

• Async API
  aliases: readdir, readdir.async, readdir.readdirAsync
  Reads the starting directory contents asynchronously and buffers all the results until all contents have been read. Supports callback or Promise syntax (see example below).

• Streaming API
  aliases: readdir.stream, readdir.readdirStream
  The streaming API reads the starting directory asynchronously and returns the results in real-time as they are read. The results can be piped to other Node.js streams, or you can listen for specific events via the EventEmitter interface. (see example below)

const readdir = require('readdir-enhanced');
const through2 = require('through2');

// Synchronous API
let files = readdir.sync('my/directory');

// Callback API
readdir.async('my/directory', function(err, files) { ... });

// Promises API
readdir.async('my/directory')
  .then(function(files) { ... })
  .catch(function(err) { ... });

// Async/Await API
let files = await readdir.async('my/directory');

// EventEmitter API
readdir.stream('my/directory')
  .on('data', function(path) { ... })
  .on('file', function(path) { ... })
  .on('directory', function(path) { ... })
  .on('symlink', function(path) { ... })
  .on('error', function(err) { ... });

// Streaming API
let stream = readdir.stream('my/directory')
  .pipe(through2.obj(function(data, enc, next) {
    console.log(data);
    this.push(data);
    next();
  });

A Note on Streams

The readdir-enhanced streaming API follows the Node.js streaming API. A lot of questions around the streaming API can be answered by reading the Node.js documentation.. However, we've tried to answer the most common questions here.

Stream Events

All events in the Node.js streaming API are supported by readdir-enhanced. These events include "end", "close", "drain", "error", plus more. An exhaustive list of events is available in the Node.js documentation.

Detect when the Stream has finished

Using these events, we can detect when the stream has finished reading files.

const readdir = require('readdir-enhanced');

// Build the stream using the Streaming API
let stream = readdir.stream('my/directory')
  .on('data', function(path) { ... });

// Listen to the end event to detect the end of the stream
stream.on('end', function() {
  console.log('Stream finished!');
});

Paused Streams vs. Flowing Streams

As with all Node.js streams, a readdir-enhanced stream starts in "paused mode". For the stream to start emitting files, you'll need to switch it to "flowing mode".

There are many ways to trigger flowing mode, such as adding a stream.data(function() { ... }) handler, using stream.pipe() or calling stream.resume().

Unless you trigger flowing mode, your stream will stay paused and you won't receive any file events.

More information on paused vs. flowing mode can be found in the Node.js documentation.

Enhanced Features

readdir-enhanced adds several features to the built-in fs.readdir() function. All of the enhanced features are opt-in, which makes readdir-enhanced fully backward compatible by default. You can enable any of the features by passing-in an options argument as the second parameter.

Recursion

By default, readdir-enhanced will only return the top-level contents of the starting directory. But you can set the deep option to recursively traverse the subdirectories and return their contents as well.

Crawl ALL subdirectories

The deep option can be set to true to traverse the entire directory structure.

const readdir = require('readdir-enhanced');

readdir('my/directory', {deep: true}, function(err, files) {
  console.log(files);
  // => subdir1
  // => subdir1/file.txt
  // => subdir1/subdir2
  // => subdir1/subdir2/file.txt
  // => subdir1/subdir2/subdir3
  // => subdir1/subdir2/subdir3/file.txt
});

Crawl to a specific depth

The deep option can be set to a number to only traverse that many levels deep. For example, calling readdir('my/directory', {deep: 2}) will return subdir1/file.txt and subdir1/subdir2/file.txt, but it won't return subdir1/subdir2/subdir3/file.txt.

const readdir = require('readdir-enhanced');

readdir('my/directory', {deep: 2}, function(err, files) {
  console.log(files);
  // => subdir1
  // => subdir1/file.txt
  // => subdir1/subdir2
  // => subdir1/subdir2/file.txt
  // => subdir1/subdir2/subdir3
});

Crawl subdirectories by name

For simple use-cases, you can use a regular expression or a glob pattern to crawl only the directories whose path matches the pattern. The path is relative to the starting directory by default, but you can customize this via options.basePath.

NOTE: Glob patterns always use forward-slashes, even on Windows. This does not apply to regular expressions though. Regular expressions should use the appropraite path separator for the environment. Or, you can match both types of separators using [\\/].

const readdir = require('readdir-enhanced');

// Only crawl the "lib" and "bin" subdirectories
// (notice that the "node_modules" subdirectory does NOT get crawled)
readdir('my/directory', {deep: /lib|bin/}, function(err, files) {
  console.log(files);
  // => bin
  // => bin/cli.js
  // => lib
  // => lib/index.js
  // => node_modules
  // => package.json
});

Custom recursion logic

For more advanced recursion, you can set the deep option to a function that accepts an fs.Stats object and returns a truthy value if the starting directory should be crawled.

NOTE: The fs.Stats object that's passed to the function has additional path and depth properties. The path is relative to the starting directory by default, but you can customize this via options.basePath. The depth is the number of subdirectories beneath the base path (see options.deep).

const readdir = require('readdir-enhanced');

// Crawl all subdirectories, except "node_modules"
function ignoreNodeModules (stats) {
  return stats.path.indexOf('node_modules') === -1;
}

readdir('my/directory', {deep: ignoreNodeModules}, function(err, files) {
  console.log(files);
  // => bin
  // => bin/cli.js
  // => lib
  // => lib/index.js
  // => node_modules
  // => package.json
});

Filtering

The filter option lets you limit the results based on any criteria you want.

Filter by name

For simple use-cases, you can use a regular expression or a glob pattern to filter items by their path. The path is relative to the starting directory by default, but you can customize this via options.basePath.

NOTE: Glob patterns always use forward-slashes, even on Windows. This does not apply to regular expressions though. Regular expressions should use the appropraite path separator for the environment. Or, you can match both types of separators using [\\/].

const readdir = require('readdir-enhanced');

// Find all .txt files
readdir('my/directory', {filter: '*.txt'});

// Find all package.json files
readdir('my/directory', {filter: '**/package.json', deep: true});

// Find everything with at least one number in the name
readdir('my/directory', {filter: /\d+/});

Custom filtering logic

For more advanced filtering, you can specify a filter function that accepts an fs.Stats object and returns a truthy value if the item should be included in the results.

NOTE: The fs.Stats object that's passed to the filter function has additional path and depth properties. The path is relative to the starting directory by default, but you can customize this via options.basePath. The depth is the number of subdirectories beneath the base path (see options.deep).

const readdir = require('readdir-enhanced');

// Only return file names containing an underscore
function myFilter(stats) {
  return stats.isFile() && stats.path.indexOf('_') >= 0;
}

readdir('my/directory', {filter: myFilter}, function(err, files) {
  console.log(files);
  // => __myFile.txt
  // => my_other_file.txt
  // => img_1.jpg
  // => node_modules
});

Base Path

By default all readdir-enhanced functions return paths that are relative to the starting directory. But you can use the basePath option to customize this. The basePath will be prepended to all of the returned paths. One common use-case for this is to set basePath to the absolute path of the starting directory, so that all of the returned paths will be absolute.

const readdir = require('readdir-enhanced');
const path = require('path');

// Get absolute paths
let absPath = path.resolve('my/dir');
readdir('my/directory', {basePath: absPath}, function(err, files) {
  console.log(files);
  // => /absolute/path/to/my/directory/file1.txt
  // => /absolute/path/to/my/directory/file2.txt
  // => /absolute/path/to/my/directory/subdir
});

// Get paths relative to the working directory
readdir('my/directory', {basePath: 'my/directory'}, function(err, files) {
  console.log(files);
  // => my/directory/file1.txt
  // => my/directory/file2.txt
  // => my/directory/subdir
});

Path Separator

By default, readdir-enhanced uses the correct path separator for your OS (\ on Windows, / on Linux & MacOS). But you can set the sep option to any separator character(s) that you want to use instead. This is usually used to ensure consistent path separators across different OSes.

const readdir = require('readdir-enhanced');

// Always use Windows path separators
readdir('my/directory', {sep: '\\', deep: true}, function(err, files) {
  console.log(files);
  // => subdir1
  // => subdir1\file.txt
  // => subdir1\subdir2
  // => subdir1\subdir2\file.txt
  // => subdir1\subdir2\subdir3
  // => subdir1\subdir2\subdir3\file.txt
});

Custom FS methods

By default, readdir-enhanced uses the default Node.js FileSystem module for methods like fs.stat, fs.readdir and fs.lstat. But in some situations, you can want to use your own FS methods (FTP, SSH, remote drive and etc). So you can provide your own implementation of FS methods by setting options.fs or specific methods, such as options.fs.stat.

const readdir = require('readdir-enhanced');

function myCustomReaddirMethod(dir, callback) {
  callback(null, ['__myFile.txt']);
}

let options = {
  fs: {
    readdir: myCustomReaddirMethod
  }
};

readdir('my/directory', options, function(err, files) {
  console.log(files);
  // => __myFile.txt
});

Get fs.Stats objects instead of strings

All of the readdir-enhanced functions listed above return an array of strings (paths). But in some situations, the path isn't enough information. So, readdir-enhanced provides alternative versions of each function, which return an array of fs.Stats objects instead of strings. The fs.Stats object contains all sorts of useful information, such as the size, the creation date/time, and helper methods such as isFile(), isDirectory(), isSymbolicLink(), etc.

NOTE: The fs.Stats objects that are returned also have additional path and depth properties. The path is relative to the starting directory by default, but you can customize this via options.basePath. The depth is the number of subdirectories beneath the base path (see options.deep).

To get fs.Stats objects instead of strings, just add the word "Stat" to the function name. As with the normal functions, each one is aliased (e.g. readdir.async.stat is the same as readdir.readdirAsyncStat), so you can use whichever naming style you prefer.

const readdir = require('readdir-enhanced');

// Synchronous API
let stats = readdir.sync.stat('my/directory');
let stats = readdir.readdirSyncStat('my/directory');

// Async API
readdir.async.stat('my/directory', function(err, stats) { ... });
readdir.readdirAsyncStat('my/directory', function(err, stats) { ... });

// Streaming API
readdir.stream.stat('my/directory')
  .on('data', function(stat) { ... })
  .on('file', function(stat) { ... })
  .on('directory', function(stat) { ... })
  .on('symlink', function(stat) { ... });

readdir.readdirStreamStat('my/directory')
  .on('data', function(stat) { ... })
  .on('file', function(stat) { ... })
  .on('directory', function(stat) { ... })
  .on('symlink', function(stat) { ... });

Backward Compatible

readdir-enhanced is fully backward-compatible with Node.js' built-in fs.readdir() and fs.readdirSync() functions, so you can use it as a drop-in replacement in existing projects without affecting existing functionality, while still being able to use the enhanced features as needed.

const readdir = require('readdir-enhanced');
let readdirSync = readdir.sync;

// Use it just like Node's built-in fs.readdir function
readdir('my/directory', function(err, files) { ... });

// Use it just like Node's built-in fs.readdirSync function
let files = readdirSync('my/directory');

Contributing

Contributions, enhancements, and bug-fixes are welcome! File an issue on GitHub and submit a pull request.

Building

To build the project locally on your computer:

1. Clone this repo
   git clone https://github.com/JS-DevTools/readdir-enhanced.git

2. Install dependencies
   npm install

3. Run the tests
   npm test

License

readdir-enhanced is 100% free and open-source, under the MIT license. Use it however you want.

Big Thanks To

Thanks to these awesome companies for their support of Open Source developers ❤