facebook/esprima — pull request #56 by gabelevi (2014-10-14 19:59:24+00:00)
Title: Support union type annotations in fb-esprima

These are pretty straightforward. Typescript wrote a good spec for
them here: https://github.com/Microsoft/TypeScript/issues/805

The one tricky thing that we don't currently have a way to parse is a type that
is function type A or function type B. You would need parens like

(() => string) | (() => number)

or type aliasing like

type A = () => string;
type B = () => number;
var x: A | B = ...;

Test Plan: npm test