ramda: dead code elimination cause problems with _arity

Some of the dead code eliminators (like babel-plugin-minify-dead-code-elimination) remove arguments from function’s definition. Which cause problem with _arity.js

from: case 2: return function(a0, a1) { return fn.apply(this, arguments); }; will become: case 2: return function() { return fn.apply(this, arguments); };

and it will cause problems in combinations like uncurryN and compose because they are depending on the function.length returned from _arity.

I would like to open discussion if _arity can be more defensive. Because the function really depends on the dead code.

One of the possible solutions can be

const arity2 = function() { return fn.apply(this, arguments);
arity2.arity = 2;
return arity2;

And then it is possible to check a function length by specified arity (if not specified than fallback to length).

What do you think about that?

problematic example:

const lastFn = curry((firstArg, secondArg) => {
  console.log("lastFn-firstArg", firstArg);
  console.log("lastFn-secondArg", secondArg);
  return "finish";
});

const firstFn = (firstArg) => {
  console.log("firstFn-firstArg", firstArg); // there will be undefined when minified
  return firstArg;
};
const incorrectBehaviour = uncurryN(2, compose(lastFn, firstFn));


you can play with this example at
https://github.com/aizerin/dead-code-issue-example
just type yarn and yarn start

I have encountered the same problem with less complicated and usual code, but I cannot remember now.

note: args elimination can be disabled in the plugin mentioned above.