Type of usePrevious is not entirely correct

[FleetAdmiralJakob]

The type of usePrevious:

usehooks/index.d.ts

Line 219 in 90fbbb4

export function usePrevious<T>(newValue: T): T;

And should be updated to:

  export function usePrevious<T>(newValue: T): T | null;

as the previous state here can be null:

usehooks/index.js

Line 1019 in 90fbbb4

const [previous, setPrevious] = React.useState(null);

Potentially related issues: #275, #316