Check synchronously if file/directory exists in Node.js

Question

How can I synchronously check, using node.js, if a file or directory exists?

Answer 1

Using the currently recommended (as of 2015) APIs (per the Node docs), this is what I do:

var fs = require('fs');

function fileExists(filePath)
{
    try
    {
        return fs.statSync(filePath).isFile();
    }
    catch (err)
    {
        return false;
    }
}

In response to the EPERM issue raised by @broadband in the comments, that brings up a good point. fileExists() is probably not a good way to think about this in many cases, because fileExists() can't really promise a boolean return. You may be able to determine definitively that the file exists or doesn't exist, but you may also get a permissions error. The permissions error doesn't necessarily imply that the file exists, because you could lack permission to the directory containing the file on which you are checking. And of course there is the chance you could encounter some other error in checking for file existence.

So my code above is really doesFileExistAndDoIHaveAccessToIt(), but your question might be doesFileNotExistAndCouldICreateIt(), which would be completely different logic (that would need to account for an EPERM error, among other things).

While the fs.existsSync answer addresses the question asked here directly, that is often not going to be what you want (you don't just want to know if "something" exists at a path, you probably care about whether the "thing" that exists is a file or a directory).

The bottom line is that if you're checking to see if a file exists, you are probably doing that because you intend to take some action based on the result, and that logic (the check and/or subsequent action) should accommodate the idea that a thing found at that path may be a file or a directory, and that you may encounter EPERM or other errors in the process of checking.