fix: support the ng-package.json in secondary entry points

docs/secondary-entrypoints.md

@@ -37,3 +37,8 @@ The contents of `my_package/testing/package.json` can be as simple as:
 No, that is not a typo. No name is required. No version is required.
 It's all handled for you by ng-packagr!
 When built, the primary entry point is imported by `import {..} from '@my/library'` and the secondary entry point with `import {..} from '@my/library/testing'`.
+
+### Alternative to `package.json`
+
+Alternatively, you could create `ng-package.json` instead of `package.json`.
+This is particularly useful in conjunction with `no-implicit-dependencies` TSLint rule, which will complain if `package.json` does not contain the dependencies used in the secondary entry point, which is misleading since all the dependencies should be mentioned in the primary `package.json`.

integration/samples/secondary/feature-d/feature-d.ts

@@ -0,0 +1,5 @@
+import { FEATURE_A } from '@sample/secondary/feature-a';
+import { FEATURE_B } from '@sample/secondary/feature-b';
+import { FEATURE_C } from '@sample/secondary/feature-c';
+
+export const FEATURE_D = `Feature D: ${FEATURE_A} ${FEATURE_B} ${FEATURE_C}`;

integration/samples/secondary/feature-d/ng-package.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "../../../../src/ng-package.schema.json",
+  "lib": {
+    "entryFile": "feature-d.ts"
+  }
+}

integration/samples/secondary/specs/ep-feature-d.ts

@@ -0,0 +1,33 @@
+import { expect } from 'chai';
+
+describe(`@sample/secondary/feature-d`, () => {
+  let PACKAGE;
+
+  before(() => {
+    PACKAGE = require('../dist/feature-d/package.json');
+  });
+
+  it(`should exist`, () => {
+    expect(PACKAGE).to.be.ok;
+  });
+
+  it(`should be named '@sample/secondary/feature-d'`, () => {
+    expect(PACKAGE['name']).to.equal('@sample/secondary/feature-d');
+  });
+
+  it(`should reference "main" bundle (UMD)`, () => {
+    expect(PACKAGE['main']).to.equal('../bundles/sample-secondary-feature-d.umd.js');
+  });
+
+  it(`should reference "module" bundle (FESM5)`, () => {
+    expect(PACKAGE['module']).to.equal('../fesm5/sample-secondary-feature-d.js');
+  });
+
+  it(`should reference "typings" files`, () => {
+    expect(PACKAGE['typings']).to.equal('sample-secondary-feature-d.d.ts');
+  });
+
+  it(`should reference "metadata" file`, () => {
+    expect(PACKAGE['metadata']).to.equal('sample-secondary-feature-d.metadata.json');
+  });
+});

src/lib/ng-v5/discover-packages.ts

@@ -32,21 +32,22 @@ function formatSchemaValidationErrors(errors: ajv.ErrorObject[]): string {
  * Resolves a user's package by testing for 'package.json', 'ng-package.json', or 'ng-package.js'.
  *
  * @param folderPathOrFilePath A path pointing either to a file or a directory
+ * @param isSecondary A boolean determining if this is a secondary package
  * @return The user's package
  */
-async function resolveUserPackage(folderPathOrFilePath: string): Promise<UserPackage | undefined> {
+async function resolveUserPackage(folderPathOrFilePath: string, isSecondary = false): Promise<UserPackage | undefined> {
   const readConfigFile = async (filePath: string) => (pathExistsSync(filePath) ? import(filePath) : undefined);
   const fullPath = path.resolve(folderPathOrFilePath);
   const pathStats = await lstat(fullPath);
   const basePath = pathStats.isDirectory() ? fullPath : path.dirname(fullPath);
   const packageJson = await readConfigFile(path.join(basePath, 'package.json'));
 
-  if (!packageJson) {
+  if (!packageJson && !isSecondary) {
     throw new Error(`Cannot discover package sources at ${folderPathOrFilePath} as 'package.json' was not found.`);
   }
 
   let ngPackageJson: undefined | object;
-  if (packageJson['ngPackage']) {
+  if (packageJson && packageJson['ngPackage']) {
     // Read `ngPackage` from `package.json`
     ngPackageJson = { ...packageJson['ngPackage'] };
   } else if (pathStats.isDirectory()) {
@@ -74,7 +75,7 @@ async function resolveUserPackage(folderPathOrFilePath: string): Promise<UserPac
 
     return {
       basePath,
-      packageJson,
+      packageJson: packageJson || {},
       ngPackageJson,
     };
   }
@@ -109,9 +110,10 @@ async function findSecondaryPackagesPaths(directoryPath: string, excludeFolder:
     '**/.git/**',
     `${path.resolve(directoryPath, excludeFolder)}/**`,
     `${directoryPath}/package.json`,
+    `${directoryPath}/ng-package.json`,
   ];
 
-  const filePaths = await globFiles(`${directoryPath}/**/package.json`, {
+  const filePaths = await globFiles(`${directoryPath}/**/{package,ng-package}.json`, {
     ignore,
     cwd: directoryPath,
   });
@@ -156,7 +158,7 @@ export async function discoverPackages({ project }: { project: string }): Promis
     .then(folderPaths =>
       Promise.all(
         folderPaths.map(folderPath =>
-          resolveUserPackage(folderPath).catch(() => {
+          resolveUserPackage(folderPath, true).catch(() => {
             log.warn(`Cannot read secondary entry point at ${folderPath}. Skipping.`);
 
             return null;