fs.exists doesn't follow the callback convention.

[petkaantonov]

On the docs it says:

File I/O is provided by simple wrappers around standard POSIX functions. To use this module do require('fs'). All the methods have asynchronous and synchronous forms.

The asynchronous form always take a completion callback as its last argument. The arguments passed to the completion callback depend on the method, but the first argument is always reserved for an exception. If the operation was completed successfully, then the first argument will be null or undefined.

But fs.exists doesn't really match that description at all.

[bnoordhuis]

fs.exists() is an anomaly and something of a wart; it started out as path.exists() but was later moved to the fs module because the path module didn't do any I/O (except for path.exists(), of course), that's why it doesn't match the other fs functions.

I've added a note to the documentation in d97ea06 that hopefully stops people from using it.