Angular 17 SSR - how to compile server files (*.mjs) to *.js

my hosting provider requires server files to be compiled to CommonJs and Angular 17 by default compiles files to Module JS *.mjs, I've tried to change the tsconfig.json but it changes the scope for the whole app but I want to change it just for server files. I've been looking for some documentation how to use something like tsconfig.server.json but I don't know how to later split it in angular.json file.

How to convert *.mjs files to *.js for SSR in Angular 17?

default tsconfig.json file:

/* To learn more about this file see: https://angular.io/config/tsconfig. */
{
  "compileOnSave": false,
  "compilerOptions": {
    "outDir": "./dist/out-tsc",
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "noImplicitOverride": true,
    "noPropertyAccessFromIndexSignature": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "esModuleInterop": true,
    "sourceMap": true,
    "declaration": false,
    "experimentalDecorators": true,
    "moduleResolution": "node",
    "importHelpers": true,
    "target": "ES2022",
    "module": "ES2022",
    "useDefineForClassFields": false,
    "lib": ["ES2022", "dom"]
  },
  "angularCompilerOptions": {
    "enableI18nLegacyMessageIdFormat": false,
    "strictInjectionParameters": true,
    "strictInputAccessModifiers": true,
    "strictTemplates": true
  }
}

Base on this idea, I found the answer, Thanks yannier

1: Modify server.ts

import 'zone.js/node';

import { APP_BASE_HREF } from '@angular/common';
import { CommonEngine } from '@angular/ssr';
import express from 'express';
import { fileURLToPath } from 'url';
import { dirname, join, resolve } from 'path';
import bootstrap from './src/main.server';

// The Express app is exported so that it can be used by serverless Functions.
export function app(): express.Express {
  const server = express();
  const serverDistFolder = dirname(fileURLToPath(import.meta.url));
  const browserDistFolder = resolve(serverDistFolder, '../browser');
  const indexHtml = join(serverDistFolder, 'index.server.html');

  const commonEngine = new CommonEngine();

  server.set('view engine', 'html');
  server.set('views', browserDistFolder);

  // Example Express Rest API endpoints
  // server.get('/api/**', (req, res) => { });
  // Serve static files from /browser
  server.get(
    '*.*',
    express.static(browserDistFolder, {
      maxAge: '1y',
    })
  );

  // All regular routes use the Angular engine
  server.get('*', (req, res, next) => {
    const { protocol, originalUrl, baseUrl, headers } = req;

    commonEngine
      .render({
        bootstrap,
        documentFilePath: indexHtml,
        url: `${protocol}://${headers.host}${originalUrl}`,
        publicPath: browserDistFolder,
        providers: [{ provide: APP_BASE_HREF, useValue: baseUrl }],
      })
      .then((html) => res.send(html))
      .catch((err) => next(err));
  });

  return server;
}

export * from './src/main.server';

2: Create a js file named main.js

async function run() {
  try {
    // Import the app from the ES module
    const server = await import("./server/server.mjs");
    const app = await server.app();

    const port = process.env["PORT"] || 4000;

    // Start up the Node server
    app.listen(port, () => {
      console.log(`Node Express server listening on http://localhost:${port}`);
    });
  } catch (error) {
    console.error("Failed to import app:", error);
  }
}

run();

3: Run main.js using node main.js or if you use iis you can run it by iisnode module:

• web.config sample for run the project in iis

<configuration>
  <system.web>
    <httpRuntime enableVersionHeader="true" />
  </system.web>
  <system.webServer>
    <httpProtocol>
      <customHeaders>
        <add name="Strict-Transport-Security" value="max-age=31536000"/>
        <add name="X-Content-Type-Options" value="nosniff" />
        <add name="X-Frame-Options" value="DENY" />
        <add name="X-XSS-Protection" value="1; mode=block" />
        <remove name="X-Powered-By" />
      </customHeaders>
    </httpProtocol>
    <webSocket enabled="false" />
    <handlers>
      <!-- Indicates that the main.js file is a node.js site to be handled by the iisnode module -->
      <add name="iisnode" path="main.js" verb="*" modules="iisnode"/>
    </handlers>
    <rewrite>
      <rules>
        <!-- <rule name="HTTP to HTTPS redirect" stopProcessing="true">
          <match url="(.*)" />
          <conditions>
            <add input="{HTTPS}" pattern="off" ignoreCase="true" />
          </conditions>
          <action type="Redirect" url="https://{HTTP_HOST}/{R:1}" redirectType="Permanent" />
        </rule> -->
        <!-- Do not interfere with requests for node-inspector debugging -->
        <rule name="NodeInspector" patternSyntax="ECMAScript" stopProcessing="true">
          <match url="^main.js\/debug[\/]?" />
        </rule>
        <!-- All other URLs are mapped to the node.js site entry point -->
        <rule name="DynamicContent">
          <match url="^(?!.*login).*$"></match>
          <conditions>
            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true"/>
          </conditions>
          <action type="Rewrite" url="main.js"/>
        </rule>
      </rules>
      <!-- <outboundRules>
        <rule name="Add Strict-Transport-Security when HTTPS" enabled="true">
          <match serverVariable="RESPONSE_Strict_Transport_Security" pattern=".*" />
          <conditions>
            <add input="{HTTPS}" pattern="on" ignoreCase="true" />
          </conditions>
          <action type="Rewrite" value="max-age=31536000" />
        </rule>
      </outboundRules> -->
    </rewrite>
    <!-- 'bin' directory has no special meaning in node.js and apps can be placed in it -->
    <security>
      <requestFiltering>
        <hiddenSegments>
          <remove segment="bin"/>
        </hiddenSegments>
      </requestFiltering>
    </security>
    <!-- Make sure error responses are left untouched -->
    <httpErrors existingResponse="PassThrough" />

    <!-- Restart the server if any of these files change -->
    <iisnode watchedFiles="web.config;*.js;browser/*.*" nodeProcessCommandLine="C:\Program Files\nodejs\node.exe" />
  </system.webServer>
</configuration>

• Output path result:

  - browser (folder)
  - server (folder)
  - main.js
  - web.config (in iis)