Node.js fs.readlink() Method

The fs.readlink() method is an inbuilt application programming interface of fs module which is used to asynchronously return a symbolic link’s value, i.e. the path it is linked to. The optional argument can be used to specify the character encoding of the link path.

Syntax:

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

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

• path: It is a string, Buffer, or URL which represents the path of the symbolic link.
• options: It is an object or string that can be used to specify optional parameters that will affect the output. It has one optional parameter:
  • encoding: It is a string value that specifies the character encoding in which the link path is returned. The default value is ‘utf8′.’
• callback: It is the function that would be called when the method is executed. 
  • err: It is an error that would be thrown if the method fails.
  • linkString: It is the string or Buffer object that contains the symbolic link’s string value.

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

Example 1: This example reads the value of symlink for a file and also changes the encoding of the value.

javascript

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

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

// Create a symbolic link
fs.symlinkSync(__dirname + "\\example_file.txt",
                       "symlinkToFile", 'file');

console.log("\nSymlink created\n");

// Using the default utf-8 encoding for the link value
fs.readlink("symlinkToFile", (err, linkString) => {
  if (err)
    console.log(err);
  else
    console.log("Path of the symlink:", linkString);
});


// Using the base64 encoding for the link value
fs.readlink("symlinkToFile",

  // Specify the options object
  {encoding: "base64"},
  (err, linkString) => {
    if (err)
      console.log(err);
    else
      console.log("Path in base64:", linkString);
});

Output:

Symlink created

Path of the symlink: G:\tutorials\nodejs-fs-readlink\example_file.txt
Path in base64: RzpcdHV0b3JpYWxzXG5vZGVqcy1mcy1yZWFkbGlua1xleGFtcGxlX2ZpbGUudHh0

Example 2: This example reads the value of a symlink for a directory.

javascript

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

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

// Create a symbolic link
fs.symlinkSync(__dirname + "\\example_directory",
            "symlinkToDir", 'dir');

console.log("\nSymlink created\n");

fs.readlink("symlinkToDir", (err, linkString) => {
  if (err)
    console.log(err);
  else
    console.log("Path of the symlink:", linkString);
});

Output:

Symlink created

Path of the symlink: G:\tutorials\nodejs-fs-readlink\example_directory

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