The `propTypes`, `contextTypes`, and `childContextTypes` APIs will work exactly as before. The only change is that the built-in validators now live in a separate package.
You may also consider using [Flow](https://flow.org/) to statically type check your JavaScript code, including [React components](https://flow.org/en/docs/frameworks/react/#setup-flow-with-react-a-classtoc-idtoc-setup-flow-with-react-hreftoc-setup-flow-with-reacta).
You may also consider using [Flow](https://flow.org/) to statically type check your JavaScript code, including [React components](https://flow.org/en/docs/react/components/).