According to the documentation node.js fs.exists() will be deprecated. Their reasoning:
fs.exists() is an anachronism and exists only for historical reasons.
Use fs.existsSync().
fs.existsSync() has not been deprecated.
https://nodejs.org/api/fs.html#fs_fs_existssync_path
fs.existsSync(path)
Added in: v0.1.21 path | Synchronous version of fs.exists(). Returns true if the file exists, false otherwise.
Note that fs.exists() is deprecated, but fs.existsSync() is not. (The callback >parameter to fs.exists() accepts parameters that are inconsistent with other >Node.js callbacks. fs.existsSync() does not use a callback.)