getPolyfill is incorrect, Array.find is always shimmed when calling .shim()

[zerovox]

var implemented = Array.prototype.find && [, 1].find(function (item, index) {
	return index === 0;
});

The comment says 'Detect early implementations which skipped holes in sparse arrays' but this code appears to return the first item in the array, which is undefined, hence implemented returns false. I believe that whole clause should be negated.

[zerovox]

I believe this bug is present in es6-shim too, filed #433 to track

[ljharb]

Thanks, I'll fix in both places.

[ljharb]

Released in v2.0.2

[zerovox]

Did you test this in chrome @ljharb? I'm pretty sure this fix has the exact same issue. The es6-shim fix looks correct though (the predicate in es6-shims means shouldShim, whereas here it means implemented)

[ljharb]

@zerovox ah crap, you're right. I forgot the negation :-) v2.0.3 coming soon.

[ljharb]

(for the record; my tests only test for proper behavior; an overzealous shim is not an observable bug, it's simply a negligible performance hit :-) )

[zerovox]

Thanks for the quick fixes! Yep, correctness wasn't an issue but the shimmed .find is unfortunately slower than the native equivalent in our use case. Might be possible to test the overzealous shimming in es6-shim with a test that shims once then mocks overrideNative and attempts to shim a second time - overrideNative should, theoretically, never be called on the second iteration.

[ljharb]

That's a very interesting idea!