@theme-ui/components/src/types.ts

Primitive layout, typographic, and other components for use with Theme UI.

export type Assign<T, U> = {
  [P in keyof (T & U)]: P extends keyof T
    ? T[P]
    : P extends keyof U
    ? U[P]
    : never
}

export interface ForwardRef<T, P>
  extends React.ForwardRefExoticComponent<
    React.PropsWithoutRef<P> & React.RefAttributes<T>
  > {}