https://reactjs.org/docs/hooks-faq.html#how-to-create-expensive-objects-lazily

useState accepts a default value OR a create function for the default value. If a function, it is evaluated only once. Thus, this entire pattern could simply be a convenience function:

import * as React from 'react' export default function useConstant<T>(fn: () => T): T { return React.useState<T>(fn)[0] }