Command

build

Description

When defining multiple routes with RenderMode.Prerender in app.routes.server.ts, such as:

{
  path: 'shop/:product',
  renderMode: RenderMode.Prerender,
  async getPrerenderParams() {
    return [
      'ccd8-123f',
      'f3ad-e1u4',
      'cvae-5ase',
    ].map(product => ({ product }));
  },
  fallback: PrerenderFallback.Server,
},
{
  path: '**',
  renderMode: RenderMode.Prerender,
},

it appears that the server is started multiple times — once per route — during ng build. This leads to the following error if the isMainModule guard is removed from server.ts:

Error: listen EADDRINUSE: address already in use :::4000

In my case, I must remove the isMainModule check to support deployment via iisnode on Azure, but doing so causes this build issue.

Minimal Reproduction

Remove isMainModule check from` server.ts:

...
const port = process.env['PORT'] || 4000;
app.listen(port, () => {
  console.log(`Node Express server listening on http://localhost:${port}`);
});
export const reqHandler = createNodeRequestHandler(app);

Have multiple routes with renderMode: RenderMode.Prerender on app.routes.server.ts.

Exception or Error

`Error: listen EADDRINUSE: address already in use :::4000`

Your Environment

Angular CLI: 19.2.8
Node: 18.19.0
Package Manager: npm 10.8.1
OS: win32 x64