brigand's react-style-proptype repo is a good example of how to do it, check that the keys given match one of a list of css properties and throw an error if it doesn't fit one of them, or the whole thing is something other than an object or undefined.
brigand's react-style-proptype repo is a good example of how to do it, check that the keys given match one of a list of css properties and throw an error if it doesn't fit one of them, or the whole thing is something other than an object or undefined.