How to read a symlink in Node.js

Question

I want to read a symlink, and get the details of the link itself, not the contents of the linked file. How do I do that in Node, in a cross-platform way?

I can detect symlinks easily using lstat, no problem. Once I know the path of the file, and that it is a symlink though, how can I read it? fs.readFile always reads the target file, or throws an error for reading a directory for links to directories.

There is a fs.constants.O_SYMLINK constant, which in theory solves this on OSX, but it seems to be undefined on both Ubuntu & Windows 10.

Answer 1

If you have determined that the file is a symlink try this:

fs.readlink("./mysimlink", function (err, linkString) { 
         // .. do some error handling here .. 
         console.log(linkString) 
});

Confirmed as working on Linux.

You could then use fs.realpath() to turn it into a full path. Be aware though that linkString can be just a filename or relative path as well as a fully qualified path so you may have to get fs.realpath() for the symlink, determine its directory part and prefix it to linkString before using fs.realpath() on it.