nx/packages/angular/src/builders/webpack-server/webpack-server.impl.ts

import {
  joinPathFragments,
  normalizePath,
  targetToTargetString,
} from '@nx/devkit';
import { existsSync } from 'fs';
import { relative } from 'path';
import { Observable, from } from 'rxjs';
import { switchMap } from 'rxjs/operators';
import { createTmpTsConfigForBuildableLibs } from '../utilities/buildable-libs';
import { mergeCustomWebpackConfig } from '../utilities/webpack';
import { Schema } from './schema';

function buildServerApp(
  options: Schema,
  context: import('@angular-devkit/architect').BuilderContext
): Observable<import('@angular-devkit/build-angular').ServerBuilderOutput> {
  const { buildLibsFromSource, customWebpackConfig, ...delegateOptions } =
    options;
  // If there is a path to custom webpack config
  // Invoke our own support for custom webpack config
  if (customWebpackConfig && customWebpackConfig.path) {
    const pathToWebpackConfig = joinPathFragments(
      context.workspaceRoot,
      customWebpackConfig.path
    );

    if (existsSync(pathToWebpackConfig)) {
      return buildServerAppWithCustomWebpackConfiguration(
        delegateOptions,
        context,
        pathToWebpackConfig
      );
    } else {
      throw new Error(
        `Custom Webpack Config File Not Found!\nTo use a custom webpack config, please ensure the path to the custom webpack file is correct: \n${pathToWebpackConfig}`
      );
    }
  }

  return from(import('@angular-devkit/build-angular')).pipe(
    switchMap(({ executeServerBuilder }) =>
      executeServerBuilder(delegateOptions, context)
    )
  );
}

function buildServerAppWithCustomWebpackConfiguration(
  options: Schema,
  context: import('@angular-devkit/architect').BuilderContext,
  pathToWebpackConfig: string
) {
  return from(import('@angular-devkit/build-angular')).pipe(
    switchMap(({ executeServerBuilder }) =>
      executeServerBuilder(options, context as any, {
        webpackConfiguration: async (baseWebpackConfig) => {
          // Angular auto includes code from @angular/platform-server
          // This includes the code outside the shared scope created by ModuleFederation
          // This code will be included in the generated code from our generators,
          // maintaining it within the shared scope.
          // Therefore, if the build is an MF Server build, remove the auto-includes from
          // the base webpack config from Angular
          let mergedConfig = await mergeCustomWebpackConfig(
            baseWebpackConfig,
            pathToWebpackConfig,
            options,
            context.target
          );

          if (mergedConfig.target === 'async-node') {
            mergedConfig.entry.main = mergedConfig.entry.main.filter(
              (m) => !m.startsWith('@angular/platform-server/init')
            );
            mergedConfig.module.rules = mergedConfig.module.rules.filter((m) =>
              !m.loader
                ? true
                : !m.loader.endsWith(
                    '@angular-devkit/build-angular/src/builders/server/platform-server-exports-loader.js'
                  )
            );
          }

          return mergedConfig;
        },
      })
    )
  );
}

export function executeWebpackServerBuilder(
  options: Schema,
  context: import('@angular-devkit/architect').BuilderContext
): Observable<import('@angular-devkit/build-angular').ServerBuilderOutput> {
  options.buildLibsFromSource ??= true;

  process.env.NX_BUILD_LIBS_FROM_SOURCE = `${options.buildLibsFromSource}`;
  process.env.NX_BUILD_TARGET = targetToTargetString({ ...context.target });

  if (!options.buildLibsFromSource) {
    const { tsConfigPath } = createTmpTsConfigForBuildableLibs(
      options.tsConfig,
      context
    );
    options.tsConfig = normalizePath(
      relative(context.workspaceRoot, tsConfigPath)
    );
  }

  return buildServerApp(options, context);
}

export default require('@angular-devkit/architect').createBuilder(
  executeWebpackServerBuilder
) as any;