Nuxt #23595 WiP workaround

router.options.ts

import type { RouteRecordRaw } from "vue-router";
import type { RouterOptions } from '@nuxt/schema';

export default {
  routes(routes) {
    if (hasChildren(routes)) {
      console.warn('The pages had children, which means the fix-pagehierarchy module can be removed!');
      return routes;
    }

    return buildHierarchy(routes as any);
  },
} satisfies RouterOptions;

function hasChildren(pages: readonly RouteRecordRaw[]) {
  return pages.some(page => page.children?.length);
}

// Workaround for Nuxt not populating the hierarchy of pages properly.
//
// See https://github.com/nuxt/nuxt/issues/23595.
function buildHierarchy(routes: readonly RouteRecordRaw[]) {
  const root: RouteRecordRaw[] = [];
  const routes2 = [...routes];
  routes2.sort((a, b) => a.path.length - b.path.length);

  for (const rec of routes2) {
    const path = parsePath(rec.path);
    let accPath = "";
    let els = root;
    for (const p of path) {
      accPath += "/" + p;
      let eli = els.findIndex((el) => el.path === accPath);
      if (eli < 0) {
        els.push({ ...rec, children: [] });
        eli = els.length - 1;
      }
      els = els[eli].children!;
    }
  }

  return root;
}

function parsePath(s: string) {
  const parts: string[] = [];
  if (s.startsWith("/")) s = s.slice(1);
  while (s) {
    const br = s.indexOf("(");
    let slash = s.indexOf("/");
    if (br >= 0 && (slash < 0 || br < slash)) {
      const bre = s.indexOf(")", br + 1);
      if (bre >= 0) slash = s.indexOf("/", bre + 1);
    }

    if (slash < 0) slash = s.length;
    parts.push(s.slice(0, slash));
    s = s.slice(slash + 1);
  }
  return parts;
}