feat: add fastify plugin implementation (#252)

Author: baryla

.changeset/pink-dogs-kneel.md

@@ -0,0 +1,5 @@
+---
+'@ts-rest/fastify': major
+---
+
+Added support for registering ts-rest as a Fastify plugin

apps/docs/docs/fastify.mdx

@@ -37,7 +37,7 @@ const router = s.router(contract, {
   },
 });
 
-s.registerRouter(contract, router, app);
+app.register(s.plugin(router));
 
 const start = async () => {
   try {

apps/docs/docs/quickstart.mdx

@@ -245,7 +245,7 @@ const router = s.router(contract, {
   },
 });
 
-s.registerRouter(contract, router, app);
+app.register(s.plugin(router));
 
 const start = async () => {
   try {

libs/ts-rest/fastify/src/lib/ts-rest-fastify.spec.ts

@@ -107,6 +107,34 @@ describe('ts-rest-fastify', () => {
     expect(response.body).toEqual({ foo: 'bar' });
   });
 
+  it('should instantiate fastify routes using plugin instance', async () => {
+    const app = fastify({ logger: false });
+
+    app.register(s.plugin(router));
+
+    await app.ready();
+
+    const response = await supertest(app.server).get('/test');
+
+    expect(response.statusCode).toEqual(200);
+    expect(response.body).toEqual({ foo: 'bar' });
+  });
+
+  it('should allow for options when using plugin instance', async () => {
+    const app = fastify({ logger: false });
+
+    app.register(s.plugin(router), {
+      responseValidation: true,
+    });
+
+    await app.ready();
+
+    const response = await supertest(app.server).get('/wrong');
+
+    expect(response.statusCode).toEqual(200);
+    expect(response.body).toEqual({ foo: 'bar' });
+  });
+
   it('should parse body correctly', async () => {
     const app = fastify({ logger: false });
 

libs/ts-rest/fastify/src/lib/ts-rest-fastify.ts

@@ -38,6 +38,11 @@ type RecursiveRouterObj<T extends AppRouter> = {
     : never;
 };
 
+type InitialisedRouter<TContract extends AppRouter> = {
+  contract: TContract;
+  routes: RecursiveRouterObj<TContract>;
+};
+
 type RegisterRouterOptions = {
   logInitialization?: boolean;
   jsonQuery?: boolean;
@@ -100,9 +105,15 @@ const validateRequest = (
 };
 
 export const initServer = () => ({
-  router: <T extends AppRouter>(router: T, args: RecursiveRouterObj<T>) => args,
+  router: <TContract extends AppRouter>(
+    contract: TContract,
+    routes: RecursiveRouterObj<TContract>
+  ): InitialisedRouter<TContract> => ({
+    contract,
+    routes,
+  }),
   registerRouter: <
-    T extends RecursiveRouterObj<TContract>,
+    T extends InitialisedRouter<TContract>,
     TContract extends AppRouter
   >(
     contract: TContract,
@@ -115,12 +126,34 @@ export const initServer = () => ({
       requestValidationErrorHandler: 'combined',
     }
   ) => {
-    recursivelyRegisterRouter(routerImpl, contract, [], app, options);
+    recursivelyRegisterRouter(routerImpl.routes, contract, [], app, options);
 
     app.setErrorHandler(
       requestValidationErrorHandler(options.requestValidationErrorHandler)
     );
   },
+  plugin:
+    <T extends AppRouter>(
+      router: InitialisedRouter<T>
+    ): fastify.FastifyPluginCallback<RegisterRouterOptions> =>
+    (
+      app,
+      opts = {
+        logInitialization: true,
+        jsonQuery: false,
+        responseValidation: false,
+        requestValidationErrorHandler: 'combined',
+      },
+      done
+    ) => {
+      recursivelyRegisterRouter(router.routes, router.contract, [], app, opts);
+
+      app.setErrorHandler(
+        requestValidationErrorHandler(opts.requestValidationErrorHandler)
+      );
+
+      done();
+    },
 });
 
 const requestValidationErrorHandler = (