Invert mixin initialization order.

[jorgebucaran]

Currently we are initializing the app, then mixins. This makes it impossible for the app to overwrite a definition added by a mixin.

Your app should have the highest precedence and not mixins.

[zaceno]

That makes sense!

[Swizz]

Totally agree !

[andyrj]

💯 agree app should take precedence

[jorgebucaran]

I'll create a PR with the changes. 💯

As a side effect, I'd prefer to drop presets (builtin mixin group merging) with this change since it complicates the implementation.

Less is more remember? @zaceno :)

[zaceno]

I don't think that the current idea of "presets" (or "mixins in mixins") is especially important anyway. In fact it only complicates things when you're trying to do things like scoped mixins.

Anyhow, presets, or bundling mixins, can still be done in an ok-nice way with array spreads.

const MyMixinPreset = [MixinA, MixinB]

app({
  mixins: [AMixin, ...MyMixinPreset, AnotherMixin],
  ...
})

EDIT: Code fences.