Only thing I still miss is noop functions are two characters. Everything else I liked is in JS now that nullish coalescing landed.

`_=>_` is technically more than two, but not by much.

Identity function is more confusing than just ()=>{} which is obviously noop because it doesn't return the input.

If you don't provide an argument, it will use undefined, which is the same thing yours returns. Maybe it's more clear, but it's about even for me.