API routes

Create the routeCopy Anchor Link

Create src/api/modules/notes/show.route.ts:

import { z } from "@hono/zod-openapi";

import { buildRoute } from "@/api/builders";

import { zodNote } from "./notes.schema";
import { sampleNotes } from "./sample-notes";

export const showNoteRoute = buildRoute({
  route: {
    method: "get",
    path: "/{id}",
    request: {
      params: z.object({ id: z.coerce.number().int().positive() }),
    },
    responses: {
      200: {
        content: { "application/json": { schema: zodNote } },
        description: "The note.",
      },
      404: { description: "No note has this id." },
    },
  },
  handler: c => {
    const { id } = c.req.valid("param");
    const note = sampleNotes.find(item => item.id === id);
    if (!note) return c.body(null, 404);

    return c.json(note, 200);
  },
});

• path: "/{id}" uses OpenAPI's parameter syntax. It is also the path a page passes to the fetcher.
• request.params validates the URL segment. Path parameters arrive as strings, so z.coerce.number() turns "2" into 2, and .int().positive() refuses everything else.
• c.req.valid("param") returns the parsed, typed value. Read inputs through c.req.valid(), never from the raw request.
• List every status the handler returns in responses. That is what lets the fetcher type both outcomes for the caller.

Body and query parameters work the same way, through request.body and request.query; the Permissions lesson adds a validated body.

Add it to the moduleCopy Anchor Link

Open src/api/modules/notes/notes.module.ts and add the route after the list route. Keep listNotesRoute:

import { buildModule } from "@/api/builders";

import { listNotesRoute } from "./list.route";
import { showNoteRoute } from "./show.route"; 

export const notesModule = buildModule({
  name: "notes",
  routes: [listNotesRoute], 
  routes: [listNotesRoute, showNoteRoute], 
});