@progrest/ssr-nest

Wires a NestJS (Fastify) app to serve a built Angular SSR app for every route its own controllers don't own. The core "glue" behind Progressive — Angular (SSR) + NestJS in a single Node.js process.

Usually you don't install this directly — npm create progressive@latest sets it up for you. Documented here for anyone wiring it into an existing Nest app, or curious how it works.

Usage

import { NestFactory } from '@nestjs/core';
import { FastifyAdapter, NestFastifyApplication } from '@nestjs/platform-fastify';
import { mountAngularSsr } from '@progrest/ssr-nest';
import { join } from 'node:path';
import { AppModule } from './app/app.module';

async function bootstrap() {
  const app = await NestFactory.create<NestFastifyApplication>(
    AppModule,
    new FastifyAdapter(),
  );

  app.setGlobalPrefix('api');

  // `angularDistPath` is the folder containing your Angular app's `browser/`
  // and `server/` subfolders, produced by `@angular/build:application` with
  // SSR enabled.
  await mountAngularSsr(app, {
    angularDistPath: join(__dirname, '../web'),
  });

  await app.listen(process.env.PORT ?? 3000, '0.0.0.0');
}

bootstrap();

Call mountAngularSsr after registering your own controllers/modules and before app.listen(). From then on:

• Static browser assets (JS/CSS bundles, favicon) are served directly.
• Any route your own @Controller()s don't match falls through to Angular's AngularNodeAppEngine for SSR rendering.

If angularDistPath doesn't exist yet (e.g. you're running Angular's own dev server, which serves everything in memory and never writes to disk), mountAngularSsr logs a warning and skips mounting instead of throwing — your Nest app still starts and serves its own routes normally.

How it works

Two things NestJS does that most integrations don't expect:

1. Nest always registers its own Fastify not-found handler on app.listen(), with no way to opt out. Instead of fighting Fastify's single setNotFoundHandler slot, mountAngularSsr installs a global exception filter that catches the NotFoundException Nest's default handler throws, and renders the Angular page there.
2. The Angular SSR bundle is pure ESM, but a Nest app compiled to CommonJS can't require() it (ERR_REQUIRE_ESM). The bridge loads it via a real dynamic import(), kept invisible to TypeScript's commonjs-target transform.

Requires

• @nestjs/common, @nestjs/platform-fastify, fastify ^11 / ^5 (peer dependencies — bring your own, matching your Nest app).
• An Angular app built with SSR enabled (ssr: true / outputMode: "server" in the Angular CLI application builder).

Full write-up: github.com/rortizv/progressive.