Summary:
Upgrade Babel from beta.40 to beta.47
There are two important breaking changes here.
- If you want an AST from the Babel `transform` functions you must pass on `ast:true` in the options.
- The `sourceType` is now the only source of truth on whether to parse with the Script or Module goal. It defaults to `script` and can also be `module` or `unambiguous`. In the `unambiguous` case it will first try to parse with the Module goal and only if it crashes it will try again with the Script goal.
Beyond that there were some fixes and some smaller changes that may affect you. See the Babel changelogs for details (https://github.com/babel/babel/tags).
Also updated the way we generate the babel helpers file.
Reviewed By: rubennorte
Differential Revision: D8075280
fbshipit-source-id: 2bb902690e8a4b19d9cada2b7b0c94812b3d4f0f
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