Fix 2 lints in core/debounce.js

[wincent]

src/core/debounce.js
  25:34  error  Unexpected 'this'                               babel/no-invalid-this
  36:18  error  Use the rest parameters instead of 'arguments'  prefer-rest-params

The use of this in this function is expected (required, even), so suppress that lint.

The use of arguments, however, isn't required, so I replaced it.

This function isn't like other debounce functions I've seen: it allows you to pass a set of default arguments at creation-time, and in the absence of arguments being passed at call-time you get the defaults. That sounds reasonable enough (although a more conventional way to do this would be to use bind()).

The weirder thing, though, is what happens if you supply defaults at creation-time and also pass arguments at call-time: in this case, the wrapped function ends up getting called with the defaults appended to the call-time args. I can't imagine a scenario in which this behavior would be non-surprising or useful, and the test suite doesn't even exercise this behavior, so perhaps this is accidental design (it does verify that default args get used in the absence of calltime args).

In any case, I am leaving the behavior intact and just making the changes to satisfy the linter. If we want, we can separately remove the weird concatenating behavior.

Usual test plan: npm run dev && npm run text && npm run start and play with demo.

Related: #990

[wincent]

Perhaps @jbalsas remembers why the debounce function does the weird concatenation thing. At least internally, there is nowhere in the project where we seem to be passing default args to debounce() (and just one place where we are passing a context).

[julien]

Just started reviewing :)

Sent from GH.