Running vite: Cannot modify fastify route without crashing.

[skogs-pa]

Running "vite" as my pnpm dev command. Happens when I edit a route handler.

6:50:39 AM [vite] Error when evaluating SSR module ./src/index.ts:
Error: Cannot add route when fastify instance is already started!

Seems like fastify has issues with SSR. My old command "nodemon" works fine since it reloads the whole server from scratch.

[axe-me]

can you provide a repro?

I could create new route without any problem.

[AlexRMU]

+1

C:\pkg\node_modules\.pnpm\[email protected]\node_modules\fastify\lib\route.js:367
            throw new FST_ERR_DUPLICATED_ROUTE(opts.method, opts.url)
                  ^
FastifyError [Error]: Method 'POST' already declared for route '/auth/login'
    at Object.addNewRoute (C:\pkg\node_modules\.pnpm\[email protected]\node_modules\fastify\lib\route.js:367:19)
    at Object.route (C:\pkg\node_modules\.pnpm\[email protected]\node_modules\fastify\lib\route.js:261:19)
    at Object.prepareRoute (C:\pkg\node_modules\.pnpm\[email protected]\node_modules\fastify\lib\route.js:167:18)
    at Object._post [as post] (C:\pkg\node_modules\.pnpm\[email protected]\node_modules\fastify\fastify.js:270:34)
    at FastifyAdapter.injectRouteOptions (C:\pkg\node_modules\.pnpm\@[email protected]_@[email protected]_@[email protected]\node_modules\@nestjs\platform-fastify\adapters\fastify-adapter.js:392:46)
    at FastifyAdapter.post (C:\pkg\node_modules\.pnpm\@[email protected]_@[email protected]_@[email protected]\node_modules\@nestjs\platform-fastify\adapters\fastify-adapter.js:129:21)
    at C:\pkg\node_modules\.pnpm\@[email protected]_@[email protected]_@[email protected][email protected][email protected]\node_modules\@nestjs\core\router\router-explorer.js:105:17
    at Array.forEach (<anonymous>)
    at C:\pkg\node_modules\.pnpm\@[email protected]_@[email protected]_@[email protected][email protected][email protected]\node_modules\@nestjs\core\router\router-explorer.js:90:29
    at Array.forEach (<anonymous>) {
  code: 'FST_ERR_DUPLICATED_ROUTE',
  statusCode: 500
}

// package.json
"@nestjs/cli": "^10.3.2",
"@nestjs/common": "^10.3.3",
"@nestjs/core": "^10.3.3",
"@nestjs/platform-fastify": "^10.3.3",
"@swc/cli": "^0.3.10",
"@swc/core": "^1.4.2",
"@swc/helpers": "^0.5.6",
"typescript": "^5.3.3",
"vite": "^5.1.4",
"vite-plugin-node": "^3.1.0",
"fastify": "^4.26.1"

// vite.config.ts
import { defineConfig } from "vite";
import { VitePluginNode as vite_plugin_node } from "vite-plugin-node";

export default defineConfig({
    plugins: [
        ...vite_plugin_node({
            adapter: "nest",
            appPath: "./src/index.ts",
            exportName: "App",
            tsCompiler: "swc",
            initAppOnBoot: true,
        }),
    ],
});

// ./src/index.ts
import { NestFactory } from "@nestjs/core";
import {
  FastifyAdapter,
  type NestFastifyApplication,
} from "@nestjs/platform-fastify";
import { AppModule } from "./app.module";
import { RawServerDefault } from "fastify";

async function create() {
  const adapter = new FastifyAdapter({});
  const app: NestFastifyApplication<RawServerDefault> =
    await NestFactory.create<NestFastifyApplication>(AppModule, adapter);
  return app;
}

export const App = create();

[AlexRMU]

It seems that this happens when several requests arrive at one endpoint, for some reason they are processed simultaneously and
at the same time they try to declare these methods.