PropTypes are supported out of the box in preact-compat. You could also use them via a preact vnode hook and the &quot;proptypes&quot; module (npm.im&#x2F;proptypes), which is just pulled from React&#x27;s codebase.  Synthetic events I&#x27;m very much open to feedback on - I tend to fire actual DOM events in my Karma tests, but it seems that less common.