@restart/hooks/esm/useRefWithInitialValueFactory.js

A set of utility and general-purpose React hooks.

import { useRef } from 'react';
const dft = Symbol('default value sigil');

/**
 * Exactly the same as `useRef` except that the initial value is set via a
 * factory function. Useful when the default is relatively costly to construct.
 *
 *  ```ts
 *  const ref = useRefWithInitialValueFactory<ExpensiveValue>(() => constructExpensiveValue())
 *
 *  ```
 *
 * @param initialValueFactory A factory function returning the ref's default value
 * @category refs
 */
export default function useRefWithInitialValueFactory(initialValueFactory) {
  const ref = useRef(dft);
  if (ref.current === dft) {
    ref.current = initialValueFactory();
  }
  return ref;
}