[zebproj]

Module file formats [0] have been around since the 80s, and they can kind of be thought of as MIDI files with sound samples embedded in them. You can get some very impressive sounding full-length tracks in only a few kilobytes.

0: https://en.wikipedia.org/wiki/Module_file

[bullen]

Do you know if they have a .js implementation? Or some lightweight C one?

[CyberDildonics]

Are you asking for library recommendations for a simple standard used extensively for the last 35 years when there are already 6 libraries linked in the wikipedia page you were given?