Function createRouteHook

packages/hono/src/shared/patchRoute.ts:35–58

* Creates the two-phase state machine for the route hook. * * - Pre-activation: collects sub-app references into a pending set. * - Post-activation: instruments sub-apps immediately at mount time.

()

 * - Post-activation: instruments sub-apps immediately at mount time.
 */
function createRouteHook(): { handle: RouteHookHandle; onSubAppMounted: (subApp: HonoAny) => void } {
  const pendingSubApps = new Set<HonoAny>();
  let activated = false;

  return {
    handle: {
      activate: () => {
        activated = true;
      },
      getPendingSubApps: () => pendingSubApps,
    },
    onSubAppMounted: (subApp: HonoAny) => {
      if (activated) {
        DEBUG_BUILD && debug.log(`[hono] Instrumenting sub-app at mount time (${subApp.routes.length} routes).`);
        wrapSubAppMiddleware(subApp.routes as HonoRoute[]);
        patchAppRequest(subApp);
      } else {
        DEBUG_BUILD &&
          debug.log(`[hono] Collecting sub-app for deferred instrumentation (${subApp.routes.length} routes).`);
        pendingSubApps.add(subApp);
      }
    },
  };
}

/**
 * Installs a hook on `HonoBase.prototype.route` to intercept sub-app mounting.