node.js - check if file exists before creating temp file

Question

I want to create a temporary file/directory in node.js. To do this, I'm attempting a simple algorithm:

1. Generate a file name based on pid, time, and random chars
2. Check if file exists
   • if yes: return to step 1 and repeat
   • if not: create the file and return it

Here's the problem: The node.js documentation for fs.exists explicitly states that fs.exists should not be used, and instead one should just use fs.open and catch a potential error: http://nodejs.org/docs/latest/api/fs.html#fs_fs_exists_path_callback

In my case, I am not interested in opening the file if it exists, I am strictly trying to find a filename that does not yet exist. Is there a way I can go about this that does not use fs.exists? Alternatively, if I do use fs.exists, should I be worried that this method will become deprecated in the future?

Answer 1

Use fs.open with the 'wx' flags instead so that you'll create the file if it doesn't exist, and return an error if it already exists.

That way you eliminate the (albeit minute) possibility that the file is created between a fs.exists check and an fs.open call to create the file.