Focus sent into a list that is still inert goes nowhere: move it after the state that lifts inert commits

import { useEffect, useRef, useState, type RefObject } from "react";
export function useReturnFocus(links: RefObject<(HTMLAnchorElement | null)[]>) {
  const [open, setOpen] = useState(-1);
  const returnTo = useRef(-1);
  // before: close() called links.current[open]?.focus() at once, while <ul inert> was still in the DOM
  const close = () => {
    returnTo.current = open;
    setOpen(-1);
  };
  useEffect(() => {
    if (open < 0 && returnTo.current >= 0) {
      links.current?.[returnTo.current]?.focus({ preventScroll: true });
      returnTo.current = -1;
    }
  }, [open, links]);
  return { open, setOpen, close }; // render the wall as <ul inert={open >= 0 || undefined}>
}