Per https://unpkg.com/prop-types@15.5.1/index.js, react is a dependency of prop-types.
However, http://npmcdn.com/prop-types/package.json does not list it as either a dependency or a peerDependency. That makes it both an implicit dependency, and one whose version compatibility is unchecked.
Could you add react as a peer dependency, ideally over the entire range of React versions that prop-types works with? I'm particularly interested in if it works on 0.13 and 0.14, I'd want the React peer dep to be ^0.13 || ^0.14 || ^15, for example.
(@acdlite @kentcdodds)