Create co.json

[blakeembrey]

Typings URL: https://github.com/types/npm-co

Questions (for new typings):

• Does the README explain the purpose of the typings and have a link to the JavaScript project?
• Do the typings follow the source structure (e.g. index.js <-> index.d.ts)?
• Are they external or global modules according the source (e.g. see README sources)?

Change Summary (for existing typings):

If anyone is interested, it's a pretty decent demonstration of TypeScript generics and how to unravel a type (E.g using <T> (arg: Promise<T> | T): Promise<T> to unravel promises and other types - in this case, thunks, iterables, etc). However, the type definition itself isn't very effective because of the limitations on generator functions in TypeScript. It appears the return type isn't even considered. Also, yielded values can't get any types either - they are always any and the input to IterableIterators is also always any.

/cc @mhegazy am I using the generators correctly? Is it possible to use the return type only or otherwise specify the result of yields?

[mhegazy]

Currently generators only capture the type of the yield expression. issue microsoft/TypeScript#2983 tracks handling it correctly and capturing the return expression type as well.