Allow begining pipe in union types

[alexandrebodin]

Hi

Everything was said in the titile. I would be great to be able to write:

union unionType = 
  | TypeA
  | Type B
  | Type C

instead of

union unionType = 
    TypeA
  | Type B
  | Type C

This would be great for prettier / graphql to make cleaner formatting. And overall go the same wayas Flow and Elm for example :)

[robzhu]

Hey @alexandrebodin, thanks for filing this issue. The proposal reasonable and we should be able to get it added soon.

[alexandrebodin]

@robzhu If you can give me some pointers I'm down for doing a PR

[robzhu]

@alexandrebodin awesome, thanks for volunteering =). Start with schema-parser-test.js:460. It has an example of parsing a union type from graphql schema format. If you trace through that, you'll probably find yourself at language/parser.js: parseUnionTypeDefinition. My general advice is to write the failing test first and work backward. I can follow up on your PR with the related spec text changes. Take a look and let me know if you still want to commit to doing this work.

[alexandrebodin]

@robzhu

PR done here: #907
(also opened a PR on the spec graphql/graphql-spec#320)

[robzhu]

Thank you for your contributions! Both PRs have been merged, closing the issue now.