Running into uncaught exceptions when trying to extract from flow

When trying to extract from flow, I get the following uncaught exception:

{ Error: (client) ../src/button/button.js (../node_modules/extract-react-types-loader!../src/button/button.js)
Module build failed (from ../node_modules/extract-react-types-loader/index.js):
TypeError: Cannot read property 'kind' of undefined
    at props.members.forEach.p ($/node_modules/extract-react-types/index.js:52:29)
    at Array.forEach (<anonymous>)
    at getPropFromObject ($/node_modules/extract-react-types/index.js:45:17)
    at getProp ($/node_modules/extract-react-types/index.js:74:12)
    at defaultProps.forEach.property ($/node_modules/extract-react-types/index.js:237:18)
    at Array.forEach (<anonymous>)
    at addDefaultProps ($/node_modules/extract-react-types/index.js:232:16)
    at convertReactComponentClass ($/node_modules/extract-react-types/index.js:263:10)
    at converters.Program ($/node_modules/extract-react-types/index.js:182:19)
    at convert ($/node_modules/extract-react-types/index.js:1433:16)
    at extractReactTypes ($/node_modules/extract-react-types/index.js:1470:10)
    at Object.extractReactTypesLoader ($/node_modules/extract-react-types-loader/index.js:65:17)

Repro: https://github.com/uber-web/baseui/pull/714/files#diff-6fabde4439377979ef1bfcd17147b620R43

[gergelyke]

So it seems that once I move the default props into the button.js file, the error goes away - any chance you can point me to where I should look for the bug in the codebase? Happy to work on a fix

[Noviny]

Looking into it quickly, it’s struggling to resolve the defaultProps. At a guess it’s the spread and the property, though it could also be a failure to grab the information from the other file.

Line 52 (or something around it) will need to be updated, but if you’re looking for the fastest way forward, I’d try some different configurations for this line as well as just checking that removing the defaults resolves the problem you are facing.