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!
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