Use babel instead of buble

[feross]

What is the purpose of this pull request? (put an "X" next to item)

[ ] Documentation update
[ ] Bug fix
[x] New feature
[ ] Other, please explain:

What changes did you make? (Give an overview)

Inspired by @hicom150's PR #1695, I swapped out buble for babel.

This way we can target just the JSX transformation. We don't use any other cutting edge JS features that require compilation, nor should we in the future.

Is there anything you'd like reviewers to focus on?

[mathiasvr]

Is this faster than buble?

[feross]

1.59s for babel vs 0.82s for buble. I think I'd rather be use babel just to be consistent with the majority of the ecosystem, even though it takes a bit longer to build.

[mathiasvr]

I’m leaning more towards buble because of speed, but I can see it doesn’t make big difference here.

What exactly becomes more consistent?
I mean is there some obvious drawbacks to using buble?

[feross]

I don't feel super strongly, but babel has these advantages:

• Most folks in the React ecosystem use it
• Lets us target just the transformations we want to apply. In this case, we transform only the JSX and don't touch any other part of the code.

[mathiasvr]

Applying JSX transformations exclusively sounds great, but in this case I prefer buble simply because it's faster.

I'm fine either way.

[hicom150]

LGTM 👍

[hicom150]

Given that buble seems to change to maintenance only mode bublejs/buble#220 I think that it is the correct time to make the transition to babel 😅

[feross]

Thanks for the review, @hicom150. I just rebased this and merged it!