While this would be fewer characters for the author to type it might not help when reading the code later. The convention of using the single _ or a prefixed _ feels easier to follow when quickly glancing through code for me personally.
I am not so much worried about the typing, so much as it feels cumbersome declaring variables I'm not going to use. I think
(_, _, param) => param
would be just as good, but unfortunately you cannot reuse the underscore. But perhaps you are right that just the _ with the variable name is not so bad.
You don't have the same intuition about the array destructing though, or would you prefer people also do?
Huh, I kind of liked this idea of omitting function parameters. I can certainly see it being annoying to figure out what to do with optional parameters - Using an underscore works ok for a single parameter, but things get awkward when there's multiple. I've certainly run into this problem a small handful of times.
Here I come again with another suggestion: What if there were a notation on the function declaration that allowed for optional positioning of those parameter values from the caller? Something like this:
function example(param1, ?param2, ?param3, param4) {
//Do whatever
}
This would work out just the same as if the following had been written instead:
The general idea is to ensure that all non-optional parameters are filled first, then fill optional parameters in order given additional available parameter data.