The closest thing you can get to the source code of FNAW. All credit goes to Lax1dude (Calder Young) for making the original game, like Eaglercraft. Originally from g.eags.us or g.lax1dude.net, this is just a mirror because the original site was blocked.
This repo contains the "source", which is just some javascript code and a tarball with the assets in it.
My fnaf fan game where you play as the janitor at my school while these erasers with creepy faces and paperclip limbs hunt you down
Playable on Github pages.