Parcel: Strip away flow types

[DeMoorJasper]

🐛 bug report

Parcel is currently not able to consume flow typed modules

🎛 Configuration (.babelrc, package.json, cli command)

N/A

🤔 Expected Behavior

Flow types should be stripped (perhaps configurable through babel)

😯 Current Behavior

Flow types cause errors

💁 Possible Solution

• locally link a copy of the module that contains flow types
• Ask the maintainer to publish the module using .flow and .js files. .flow being the typed one and .js being processed by babel to strip away the typings
• Make parcel automagically detect and strip away flow types (in node modules only)

🔦 Context

Issue #1799

💻 Code Sample

import Typography from 'typography';

cc @chiefGui

[DeMoorJasper]

So I think we can just automatically detect flow and apply the babel plugin by looking at the first line as it should say: // @flow?

[chiefGui]

Another possible solution:

If we can detect a module that contains flow types (in order to locally link it), wouldn't be less-workaroundish to make parcel apply the transform right away, exclusively against that module?

[DeMoorJasper]

Yeah I think that'll be the best approach @chiefGui , currently doing some research on flow to make sure the annotation on the first line is really required. So I don't make assumptions of a framework I've never used

[chiefGui]

According to their website:

Don’t forget to mention @flow on top of file, otherwise flow won’t report errors.

Also from the short period of time I've worked with Flow, I also do remember that I was required to annotate my files with @flow.

Finally, seems like in the Typography's case, they're also consistently using @flow (though I know one library isn't enough to say anything.).

This is just a support to help you on your research.