@bnoordhuis Is there any overhead to having these unused arguments? If not, I'd say leave them. Otherwise, the change looks fine.

I proposed the change for more consistency with the rest of fs.js where the callbacks do not reference unused parameters

I believe that mismatched parameter counts are less efficient because it forces the function call to go through an intermediate 'adapter' stack frame first. It probably also forces spilling all arguments to the stack instead of passing them in registers.

An adapter frame could perhaps be skipped when the callee's parameter count is less than that of the caller. I don't believe V8 applies any such optimizations, though.

@bnoordhuis is that something we need to investigate in more detail?

This is mostly a style-fix, so, closing for now.

@Fishrock123 Not really, it's primarily a V8 issue.