@foodsy-app/fastify-typebox

Plugin for Fastify to prevent having to write duplicate type definitions for schemas.

@foodsy-app/fastify-typebox uses typebox, to compose JSON schemas.

Important note before using this plugin!

This plugin requires patch-package to comment existing type declarations for request methods in node_modules/fastify/types/instance.d.ts since TypeScript does not allow to overwrite declarations.

Create a fastify+3.1.1.patch file (edit the version based on the Fastify version you have installed) and paste the block below inside:

diff --git a/node_modules/fastify/types/instance.d.ts b/node_modules/fastify/types/instance.d.ts
index 06380bd..558338d 100644
--- a/node_modules/fastify/types/instance.d.ts
+++ b/node_modules/fastify/types/instance.d.ts
@@ -66,14 +66,14 @@ export interface FastifyInstance<
     ContextConfig = ContextConfigDefault
   >(opts: RouteOptions<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig>): FastifyInstance<RawServer, RawRequest, RawReply, Logger>;

-  get: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
-  head: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
-  post: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
-  put: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
-  delete: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
-  options: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
-  patch: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
-  all: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
+  // get: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
+  // head: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
+  // post: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
+  // put: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
+  // delete: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
+  // options: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
+  // patch: RouteShorthandMethod<RawServer, RawRequest, RawReply>;
+  // all: RouteShorthandMethod<RawServer, RawRequest, RawReply>;

   // addHook: overloads

After this, run the following command:

npx patch-package --patch-dir .

Run the same command using the --reverse flag if you notice any problems.

Tip

Add the patch file to your source control and add the script below to the scripts section in your package.json so that people who install your project do not have to manually apply the patch:

"scripts": {
  "postinstall": "npx patch-package --patch-dir ."
}

Install

npm i @foodsy-app/fastify-typebox @sinclair/typebox
# Or if you are using Yarn
yarn add @foodsy-app/fastify-typebox @sinclair/typebox

Usage

Add it to your project using register and you are done!

import fastify from "fastify";

fastify.register(require("@foodsy-app/fastify-typebox"));

Examples

This plugin exposes a new method on the FastifyInstance called typeboxSchema

Basic usage

Notice: Please refer to the typebox repository for a overview of the typebox API.

import { Type } from "@sinclair/typebox";

// Available request methods are
// .get, .head, .post, .put, .delete, .options, .patch and .all
server.get(
  "/secret-route/:id",
  {
    schema: server.typeboxSchema({
      // You can also type querystring, headers and response
      params: Type.Object({
        id: Type.String(),
      }),
      body: Type.Object({
        user: Type.Object({
          name: Type.String(),
          age: Type.Number({ minimum: 18 }),
        }),
      }),
    }),
  },
  (request, reply) => {
    // `id` is inferred as string
    const id = request.params.id;

    // `user` is inferred as the object we described!
    const user = request.body.user;
  }
);