Babel does it in the best possible way. Namely:
- By default, it only enables features from specs that are in Draft, Candidate, or Finished stages.
- If you want to enable anything more cutting edge, you have enable it.
Default is exactly how we were processing your Babel, until now. Default (or "stage 2 and above" on their chart) is probably a good way to write production code. But CodePen isn't typically a place for production code. It's often a place for experimentation. So, we've enabled Stage 0 and Stage 1 features as well.
So you can use those things as well now: