Useful React Prop Type Examples

export declare interface AppProps {
children1: JSX.Element; // bad, doesnt account for arrays
children2: JSX.Element | JSX.Element[]; // meh, doesn't accept strings
children3: React.ReactChildren; // despite the name, not at all an appropriate type; it is a utility
children4: React.ReactChild[]; // better
children: React.ReactNode; // best, accepts everything
functionChildren: (name: string) => React.ReactNode; // recommended function as a child render prop type
style?: React.CSSProperties; // to pass through style props
onChange?: React.FormEventHandler<HTMLInputElement>; // form events! the generic parameter is the type of event.target
// more info: https://react-typescript-cheatsheet.netlify.app/docs/advanced/patterns_by_usecase/#wrappingmirroring
props: Props & React.ComponentPropsWithoutRef<"button">; // to impersonate all the props of a button element and explicitly not forwarding its ref
props2: Props & React.ComponentPropsWithRef<MyButtonWithForwardRef>; // to impersonate all the props of MyButtonForwardedRef and explicitly forwarding its ref
}
JSX.Element vs React.ReactNode?

Quote @ferdaber: A more technical explanation is that a valid React node is not the same thing as what is returned by React.createElement. Regardless of what a component ends up rendering, React.createElement always returns an object, which is the JSX.Element interface, but React.ReactNode is the set of all possible return values of a component.

  • JSX.Element -> Return value of React.createElement
  • React.ReactNode -> Return value of a component

More discussion: Where ReactNode does not overlap with JSX.Element

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