fs.access() determines whether a path exists and what permissions a user has to the file or directory at that path.

fs.access doesn't return a result rather, if it doesn't return an error, the path exists and the user has the desired
permissions.

The permission modes are available as a property on the fs object, fs.constants

• fs.constants.F_OK - Has read/write/execute permissions (If no mode is provided, this is the default)
• fs.constants.R_OK - Has read permissions
• fs.constants.W_OK - Has write permissions
• fs.constants.X_OK - Has execute permissions (Works the same as fs.constants.F_OK on Windows)

Asynchronously Check Permissions of a File or Directory

 var fs = require('fs'); var path = '/path/to/check'; // checks execute permission fs.access(path, fs.constants.X_OK, (err) => { if (err) { console.log("%s doesn't exist", path); } else { console.log('can execute %s', path); } }); // Check if we have read/write permissions // When specifying multiple permission modes // each mode is separated by a pipe : `|` fs.access(path, fs.constants.R_OK | fs.constants.W_OK, (err) => { if (err) { console.log("%s doesn't exist", path); } else { console.log('can read/write %s', path); } }); 

Synchronously Check Permissions of a File or Directory

fs.access also has a synchronous version fs.accessSync. When using fs.accessSync you must enclose it within a try/catch block.

 // Check write permission try { fs.accessSync(path, fs.constants.W_OK); console.log('can write %s', path); } catch (err) { console.log("%s doesn't exist", path); } 

With all that being said, I highly recommend you keep learning!

Thank you for reading this article. Please feel free to connect with me on LinkedIn and Twitter.