Node.js fs.readdirSync() Method

The fs.readdirSync() method is used to synchronously read the contents of a given directory. The method returns an array with all the file names or objects in the directory. The options argument can be used to change the format in which the files are returned from the method.

Syntax:

fs.readdirSync( path, options )

Parameters: This method accept two parameters as mentioned above and described below:

• path: It holds the path of the directory from where the contents have to be read. It can be a String, Buffer or URL.
• options: It is an object that can be used to specify optional parameters that will affect the method. It has two optional parameters:
  • encoding: It is a string value which specifies which encoding would be used for the filenames given to the callback argument. The default value is ‘utf8’.
  • withFileTypes: It is a boolean value which specifies whether the files would be returned as fs.Dirent objects. The default value is ‘false’.

Returns: It returns an array of String, Buffer or fs.Dirent objects that contain the files in the directory.

Below examples illustrate the fs.readdirSync() method in Node.js:

Example 1: This example uses fs.readdirSync() method to return the file names or file objects in the directory.

// Node.js program to demonstrate the
// fs.readdirSync() method

// Import the filesystem module
const fs = require('fs');

// Function to get current filenames
// in directory
filenames = fs.readdirSync(__dirname);

console.log("\nCurrent directory filenames:");
filenames.forEach(file => {
  console.log(file);
});

// Function to get current filenames
// in directory with "withFileTypes"
// set to "true"

fileObjs = fs.readdirSync(__dirname, { withFileTypes: true });

console.log("\nCurrent directory files:");
fileObjs.forEach(file => {
  console.log(file);
});

Output:

Current directory filenames:
CONTRUBUTIONS.txt
index.html
index.js
package.json
README.md

Current directory files:
Dirent { name: 'CONTRUBUTIONS.txt', [Symbol(type)]: 1 }
Dirent { name: 'index.html', [Symbol(type)]: 1 }
Dirent { name: 'index.js', [Symbol(type)]: 1 }
Dirent { name: 'package.json', [Symbol(type)]: 1 }
Dirent { name: 'README.md', [Symbol(type)]: 1 }

Example 2: This example uses fs.readdirSync() method to return only the filenames with the “.md” extension.

// Node.js program to demonstrate the
// fs.readdirSync() method

// Import the filesystem module
const fs = require('fs');
const path = require('path');

// Function to get current filenames
// in directory with specific extension
files = fs.readdirSync(__dirname);

console.log("\Filenames with the .md extension:");
files.forEach(file => {
  if (path.extname(file) == ".md")
    console.log(file);
})

Output:

Filenames with the .md extension:
README.md

Reference: https://nodejs.org/api/fs.html#fs_fs_readdirsync_path_options