PropTypes – stackoverflow link
Typescript and PropTypes serve different purposes. Typescript validates types at compile time, whereas PropTypes are checked at runtime.
Typescript is useful when you are writing code: it will warn you if you pass an argument of the wrong type to your React components, give you autocomplete for function calls, etc.
PropTypes are useful when you test how the components interact with external data, for example when you load JSON from an API. PropTypes will help you debug (when in React’s Development mode) why your component is failing
It is possible to automatically generate PropTypes from Typescript so that you don’t have to specify types twice