feat(bundling): rollup should support ESM config files

e2e/rollup/src/rollup.test.ts

@@ -13,7 +13,7 @@ import {
 import { join } from 'path';
 
 describe('Rollup Plugin', () => {
-  beforeAll(() => newProject());
+  beforeAll(() => newProject({ packages: ['@nx/rollup', '@nx/js'] }));
   afterAll(() => cleanupProject());
 
   it('should be able to setup project to build node programs with rollup and different compilers', async () => {
@@ -119,4 +119,46 @@ describe('Rollup Plugin', () => {
     runCLI(`generate @nx/js:lib ${jsLib} --bundler rollup`);
     expect(() => runCLI(`build ${jsLib}`)).not.toThrow();
   });
+
+  it('should be able to build libs generated with @nx/js:lib --bundler rollup with a custom rollup.config.{cjs|mjs}', () => {
+    const jsLib = uniq('jslib');
+    runCLI(`generate @nx/js:lib ${jsLib} --bundler rollup`);
+    updateFile(
+      `libs/${jsLib}/rollup.config.cjs`,
+      `module.exports = {
+        output: {
+          format: "cjs",
+          dir: "dist/test",
+          name: "Mylib",
+          entryFileNames: "[name].cjs.js",
+          chunkFileNames: "[name].cjs.js"
+        }
+      }`
+    );
+    updateJson(join('libs', jsLib, 'project.json'), (config) => {
+      config.targets.build.options.rollupConfig = `libs/${jsLib}/rollup.config.cjs`;
+      return config;
+    });
+    expect(() => runCLI(`build ${jsLib}`)).not.toThrow();
+    checkFilesExist(`dist/test/index.cjs.js`);
+
+    updateFile(
+      `libs/${jsLib}/rollup.config.mjs`,
+      `export default {
+        output: {
+          format: "es",
+          dir: "dist/test",
+          name: "Mylib",
+          entryFileNames: "[name].mjs.js",
+          chunkFileNames: "[name].mjs.js"
+        }
+      }`
+    );
+    updateJson(join('libs', jsLib, 'project.json'), (config) => {
+      config.targets.build.options.rollupConfig = `libs/${jsLib}/rollup.config.mjs`;
+      return config;
+    });
+    expect(() => runCLI(`build ${jsLib}`)).not.toThrow();
+    checkFilesExist(`dist/test/index.mjs.js`);
+  });
 });

packages/rollup/src/executors/rollup/rollup.impl.spec.ts

@@ -1,11 +1,15 @@
 import { ExecutorContext } from '@nx/devkit';
+import * as fs from 'fs';
 import * as rollup from 'rollup';
 import { RollupExecutorOptions } from './schema';
 import { createRollupOptions } from './rollup.impl';
 import { normalizeRollupExecutorOptions } from './lib/normalize';
 
 jest.mock('rollup-plugin-copy', () => jest.fn());
-
+jest.mock('fs', () => ({
+  ...jest.requireActual('fs'),
+  readdirSync: () => [],
+}));
 describe('rollupExecutor', () => {
   let context: ExecutorContext;
   let testOptions: RollupExecutorOptions;
@@ -35,8 +39,8 @@ describe('rollupExecutor', () => {
   });
 
   describe('createRollupOptions', () => {
-    it('should create rollup options for valid config', () => {
-      const result: any = createRollupOptions(
+    it('should create rollup options for valid config', async () => {
+      const result: any = await createRollupOptions(
         normalizeRollupExecutorOptions(
           testOptions,
           { root: '/root' } as any,
@@ -73,7 +77,7 @@ describe('rollupExecutor', () => {
         () => (o) => ({ ...o, prop: 'my-val' }),
         { virtual: true }
       );
-      const result: any = createRollupOptions(
+      const result: any = await createRollupOptions(
         normalizeRollupExecutorOptions(
           { ...testOptions, rollupConfig: 'custom-rollup.config.ts' },
           { root: '/root' } as any,
@@ -85,6 +89,7 @@ describe('rollupExecutor', () => {
         '/root/src',
         []
       );
+
       expect(result.map((x) => x.prop)).toEqual(['my-val', 'my-val']);
     });
 
@@ -103,7 +108,7 @@ describe('rollupExecutor', () => {
         }),
         { virtual: true }
       );
-      const result: any = createRollupOptions(
+      const result: any = await createRollupOptions(
         normalizeRollupExecutorOptions(
           {
             ...testOptions,
@@ -121,15 +126,16 @@ describe('rollupExecutor', () => {
         '/root/src',
         []
       );
+
       expect(result.map((x) => x.prop1)).toEqual([
         'my-val-my-val-2',
         'my-val-my-val-2',
       ]);
       expect(result.map((x) => x.prop2)).toEqual(['my-val-2', 'my-val-2']);
     });
 
-    it(`should always use forward slashes for asset paths`, () => {
-      createRollupOptions(
+    it(`should always use forward slashes for asset paths`, async () => {
+      await createRollupOptions(
         {
           ...normalizeRollupExecutorOptions(
             testOptions,
@@ -156,8 +162,8 @@ describe('rollupExecutor', () => {
       });
     });
 
-    it(`should treat npm dependencies as external if external is all`, () => {
-      const options = createRollupOptions(
+    it(`should treat npm dependencies as external if external is all`, async () => {
+      const options = await createRollupOptions(
         normalizeRollupExecutorOptions(
           { ...testOptions, external: 'all' },
           { root: '/root' } as any,
@@ -177,8 +183,8 @@ describe('rollupExecutor', () => {
       expect(external('rxjs', '', false)).toBe(false);
     });
 
-    it(`should not treat npm dependencies as external if external is none`, () => {
-      const options = createRollupOptions(
+    it(`should not treat npm dependencies as external if external is none`, async () => {
+      const options = await createRollupOptions(
         normalizeRollupExecutorOptions(
           { ...testOptions, external: 'none' },
           { root: '/root' } as any,
@@ -198,8 +204,8 @@ describe('rollupExecutor', () => {
       expect(external('rxjs', '', false)).toBe(false);
     });
 
-    it(`should set external based on options`, () => {
-      const options = createRollupOptions(
+    it(`should set external based on options`, async () => {
+      const options = await createRollupOptions(
         normalizeRollupExecutorOptions(
           { ...testOptions, external: ['rxjs'] },
           { root: '/root' } as any,

packages/rollup/src/executors/rollup/rollup.impl.ts

@@ -28,6 +28,7 @@ import { analyze } from './lib/analyze-plugin';
 import { deleteOutputDir } from '../../utils/fs';
 import { swc } from './lib/swc-plugin';
 import { updatePackageJson } from './lib/update-package-json';
+import { loadConfigFile } from '@nx/devkit/src/utils/config-utils';
 
 export type RollupExecutorEvent = {
   success: boolean;
@@ -74,7 +75,7 @@ export async function* rollupExecutor(
     .filter((d) => d.target.startsWith('npm:'))
     .map((d) => d.target.slice(4));
 
-  const rollupOptions = createRollupOptions(
+  const rollupOptions = await createRollupOptions(
     options,
     dependencies,
     context,
@@ -155,14 +156,14 @@ export async function* rollupExecutor(
 
 // -----------------------------------------------------------------------------
 
-export function createRollupOptions(
+export async function createRollupOptions(
   options: NormalizedRollupExecutorOptions,
   dependencies: DependentBuildableProjectNode[],
   context: ExecutorContext,
   packageJson: PackageJson,
   sourceRoot: string,
   npmDeps: string[]
-): rollup.InputOptions[] {
+): Promise<rollup.InputOptions[]> {
   const useBabel = options.compiler === 'babel';
   const useTsc = options.compiler === 'tsc';
   const useSwc = options.compiler === 'swc';
@@ -195,7 +196,7 @@ export function createRollupOptions(
     options.format = ['cjs'];
   }
 
-  return options.format.map((format, idx) => {
+  const _rollupOptions = options.format.map(async (format, idx) => {
     // Either we're generating only one format, so we should bundle types
     // OR we are generating dual formats, so only bundle types for CJS.
     const shouldBundleTypes = options.format.length === 1 || format === 'cjs';
@@ -310,10 +311,35 @@ export function createRollupOptions(
       plugins,
     };
 
-    return options.rollupConfig.reduce((currentConfig, plugin) => {
-      return require(plugin)(currentConfig, options);
-    }, rollupConfig);
+    const userDefinedRollupConfigs = options.rollupConfig.map((plugin) =>
+      loadConfigFile(plugin)
+    );
+    let finalConfig: rollup.InputOptions = rollupConfig;
+    for (const _config of userDefinedRollupConfigs) {
+      const config = await _config;
+      if (typeof config === 'function') {
+        finalConfig = config(finalConfig, options);
+      } else {
+        finalConfig = {
+          ...finalConfig,
+          ...config,
+          plugins: [
+            ...(finalConfig.plugins?.length > 0 ? finalConfig.plugins : []),
+            ...(config.plugins?.length > 0 ? config.plugins : []),
+          ],
+        };
+      }
+    }
+
+    return finalConfig;
   });
+
+  const rollupOptions = [];
+  for (const rollupOption of _rollupOptions) {
+    rollupOptions.push(await rollupOption);
+  }
+
+  return rollupOptions;
 }
 
 function createTsCompilerOptions(