Separate mesh by loose parts

I’ve created a some basic model in Blender. It’s 4 times subdivided cube (I need faces to look like squares), then faces was split by edges (in Blender too). Then I need to separate final mesh by loose parts in threejs (if I do that in Blender the exported file is too big, like a few MB big). So each face become separate one.

How should I do that?