Support type spread in flow-types

[StokeMasterJack]

Flow supports the below syntax but babel (or one of the tools used by create-react-app) fails to compile the file. Giving this error:

Module build failed: TypeError: Cannot read property 'typeAnnotation' of undefined

type Data = {
  firstName: string,
  lastName: string,
};

type State = {
  ...Data,
  isNew: boolean
};

[gaearon]

Need someone to help investigate why. Maybe we need to update Babel version or something.

[Timer]

We should probably upgrade all development tooling packages before the 0.10 release.

[gaearon]

Yea.

[kmiyashiro]

Has anyone tracked this down? I've tried upgrading all dependencies related to babel, flow and eslint, but I'm still getting this error when I use spread in type objects.

[kmiyashiro]

I don't know what's going on babel/babel-eslint#443

[chiptus]

For now we can use intersection types:

type State = Data & {
  isNew: boolean
};

although if Data has isNew prop that is not boolean it will end with an intersection type that might be invalid, for example:

type Data = {
  isNew: string
}

then State will end up:

type State = {
  isNew: string & boolean
}

[gaearon]

I verified this no longer reproduces in 2.x alphas. You can try them: #3815.