Node.js fs.opendir() Method

Last Updated : 08 Oct, 2021

The fs.opendir() method is used to asynchronously open a directory in the file system. It creates an fs.Dir object that is used to represent the directory. This object contains various methods that can be used to accessing the directory. Syntax:

fs.opendir( path[, options], callback )

Parameters: This method accepts three parameters as mentioned above and described below:

path: It is a String, Buffer or URL that denotes the path of the directory that has to be opened.
options: It is an String or an object that can be used to specify optional parameters that will affect the output. It has two optional parameters:
- encoding: It is a string that specifies the encoding for the path when opening the directory and for subsequent read operations. The default value is 'utf8'.
- bufferSize: It is a number that specifies the number of directory entries that are buffered internally when the directory is being read. A higher value means more performance but leads to higher memory usage. The default value is '32'.
callback: It is a function that would be called when the method is executed.
- err: It is an error that would be thrown if the method fails.
- dir: It is an fs.Dir object created by the method that represents the directory.

Below examples illustrate the fs.opendir() method in Node.js: Example 1:

javascript

// Node.js program to demonstrate the // fs.opendir() method  // Import the filesystem module const fs = require('fs');  // Open the directory console.log("Opening the directory"); fs.opendir(      // Path of the directory   "example_dir",    // Options for modifying the operation   { encoding: "utf8", bufferSize: 64 },    // Callback with the error and returned   // directory   (err, dir) => {     if (err) console.log("Error:", err);     else {       // Print the pathname of the directory       console.log("Path of the directory:", dir.path);        // Close the directory       console.log("Closing the directory");       dir.closeSync();     }   } );

Output:

  Opening the directory  Path of the directory: example_dir  Closing the directory

Example 2:

javascript

// Node.js program to demonstrate the // fs.opendir() method  // Import the filesystem module const fs = require('fs');  // Function to get current filenames // in directory filenames = fs.readdirSync("example_dir");  console.log("\nCurrent filenames in directory:"); filenames.forEach((file) => {   console.log(file); });  // Open the directory fs.opendir("example_dir", (err, dir) => {   if (err) console.log("Error:", err);   else {     // Print the pathname of the directory     console.log("\nPath of the directory:", dir.path);      // Read the files in the directory     // as fs.Dirent objects     console.log("First Dirent:", dir.readSync());     console.log("Next Dirent:", dir.readSync());     console.log("Next Dirent:", dir.readSync());   } });

Output:

  Current filenames in directory:  file_a.txt  file_b.txt    Path of the directory: example_dir  First Dirent: Dirent { name: 'file_a.txt', [Symbol(type)]: 1 }  Next Dirent: Dirent { name: 'file_b.txt', [Symbol(type)]: 1 }  Next Dirent: null

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