# Defining routes

A full exemple of [a monorepo using pnpm workspaces can be found here](https://github.com/JeromeBu/shared-routes-demo).

### API

`shared-routes` exposes 2 functions for defining routes, that should be used together

#### defineRoutes

It takes a record of routes as the only argument. And it returns the same thing.

A validation is run to make sure you do not define twice a route with the same `method` and `url.`

```typescript
type DefineRoutes = <T extends Record<string, SharedRoutes>>(routes: T) => T
```

#### defineRoute

Very useful to create routes, and is necessary to insure good type inference. The parameters are given as an object, with the following keys:

```typescript
type DefineRouteParams = {
    // method and url are required
    method: "get" | "post" | "put" | "patch" | "delete",
    url: string // must be a relative ('/something') or absolute url ('https://placeholder.com')
    
    // the following are optionnal, and will be considered void if not provided
    requestBodySchema: z.Schema<RequestBody>,
    queryParamsSchema: z.Schema<QueryParams>,
    headersSchema: z.Schema<Headers>,
    responses: {
      [statusCode]: z.Schema<Responses>,
    }
}
```

It is important to note that all the type safety and inference will comme from these definitions. It is important that they are accurate. `RequestBody`, `QueryParams`, `Headers` and `Responses` will be directly infered from the zod schemas.

### Example

The whole documentation will be referencing the following route definitions&#x20;

```typescript
import { defineRoute, defineRoutes } from "shared-routes";
import { z } from "zod";

const bookSchema = z.object({
  id: z.string(),
  title: z.string(),
  author: z.string(),
});
type Book = z.infer<typeof bookSchema>;

export const bookRoutes = defineRoutes({
  getBooks: defineRoute({
    // you have to define the method and the url :
    method: "get",
    url: "/books", // can be absolute or relative
    // you can define the query params, and the response body :
    queryParamsSchema: z.object({
      titleContains: z.string().optional(),
      authorContains: z.string().optional(),
    }),
    responses: { 200: z.array(bookSchema) },
  }),

  addBook: defineRoute({
    method: "post",
    url: "/books",
    // you can define specific headers :
    headersSchema: z.object({
      authorization: z.string(),
    }),
    // you can define the request body :
    requestBodySchema: z.object({
      title: z.string(),
      author: z.string(),
    }),
    responses: { 201: z.object({ bookId: z.number() }) },
  }),
  // you can also define the path params :
  getBookById: defineRoute({
    method: "get",
    url: "/books/:bookId",
    responses: {
      200: bookSchema,
      404: z.void(),
    },
  }),
});
```

### Use it where needed

You can now take advantage of the routes definitions with many different adapters:

* [Fetch (browser or node-fetch)](/shared-routes/adapters/fetch-browser-or-node-fetch.md)
* [Axios](/shared-routes/adapters/axios.md)
* [Express](/shared-routes/adapters/express.md)
* [Supertest](/shared-routes/adapters/supertest.md)
* [OpenAPI](/shared-routes/adapters/openapi.md)


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