TypeScript Mastery

Sirou leverages advanced TypeScript features like Template Literal Types, Recursive Conditional Types, and Mapped Types to provide zero cost type safety.

1. Inferring Parameters

You can use Sirou's internal types to extract param requirements from your schema. This is useful for building custom components that wrap Sirou hooks.

import { InferParams } from "@sirou/core";
import { type AppRoutes } from "./routes";

// Extract params for a specific route
type DetailsParams = InferParams<AppRoutes, "products.details">;
// Result: { productId: string }

2. Generating Full Route Maps

If you want a flat list of every possible route string in your app:

import { FlatRouteMap } from "@sirou/core";

export type AllPaths = keyof FlatRouteMap<AppRoutes>;
// Result: "home" | "products.list" | "products.details" | ...

3. Strict Meta Types

You can enforce a specific structure for your meta objects by passing a Generic to defineRoutes.

interface MyMeta {
  title: string;
  requiresAuth?: boolean;
}

export const routes = defineRoutes<MyMeta>({
  home: {
    path: "/",
    meta: { title: "Home" }, // Valid
    // meta: { foo: "bar" } // Error: Property 'foo' does not exist
  },
});

4. Type-Safe Redirects

When returning a redirect from a guard, Sirou ensures the target route and its params are valid.

execute: async () => {
  return {
    allowed: false,
    redirect: { name: "login", params: {} }, // Type checked!
  };
};

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Sirou's type system is designed to be "Sound but Flexible." It catches errors without getting in your way.

Next: Preparing for change with the Migration Guide.