JSON.parse(fs.readFileSync()) returning a buffer – string of numbers

fs.readFileSync() returns a Buffer if you don’t specify an encoding.

https://nodejs.org/api/fs.html#fs_fs_readfilesync_path_options

So, tell fs.readFileSync() what encoding to use:

squadJSON = JSON.parse(fs.readFileSync('./squads/squad' + whichSquad + '.json', 'utf8'));