Sirou

Logic Guards

Logic Guards are asynchronous functions that control access to your routes. They allow you to prevent unauthorized entry, perform redirects, or handle complex business logic before a navigation is finalized.

Guard Anatomy

A guard receives a context object and returns a GuardResult.

typescript
interface GuardContext {
  route: string;
  params: Record<string, any>;
  query: Record<string, string>;
  meta: any;
  router: SirouRouter;
}

type GuardResult =
  | { allowed: true }
  | { allowed: false; redirect: string | RedirectObject };

Implementation

Register your guards on the router instance.

typescript
router.registerGuard({
  name: "auth",
  execute: async ({ meta }) => {
    const user = await checkAuth();

    if (!user && meta.requiresAuth) {
      return {
        allowed: false,
        redirect: "/login",
      };
    }

    return { allowed: true };
  },
});

Why use Logic Guards?

Centralized Logic

Keep your auth and permission logic in one place instead of repeating `useEffect` checks in every component.

Platform Agnostic

Use the same guard logic on your Svelte web app and your React Native mobile app.

Type Safe Context

Guards have access to fully typed parameters and metadata from your route schema.

Multi-Guard Execution

You can apply multiple guards to a single route. Sirou executes them in the order defined in your schema.

typescript
export const routes = defineRoutes({
  admin: {
    path: "/admin",
    guards: ["auth", "isAdmin"],
  },
});

Next: Master data fetching with Data Loaders.

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