angular · alan-agius4 · Oct 1, 2026 · Sep 30, 2026
diff --git a/packages/angular/build/src/builders/library/builder.ts b/packages/angular/build/src/builders/library/builder.ts
@@ -24,14 +24,11 @@ import { purgeStaleBuildCache } from '../../utils/purge-cache';
 import { getSupportedBrowsers } from '../../utils/supported-browsers';
 import { assertCompatibleAngularVersion } from '../../utils/version';
 import type { BuildWatcher } from '../../utils/watcher';
-import {
-  type NormalizedLibraryOptions,
-  type PackageJsonData,
-  normalizeLibraryOptions,
-} from './options';
-import type { SingleBuildState } from './pipeline/build-action';
+import { normalizeLibraryOptions } from './options';
+import { updateWatchedEntryPoints } from './pipeline/entry-points';
 import type { createComponentStylesheetBundlerForLibrary } from './pipeline/stylesheet-bundler';
 import type { Schema as LibraryBuilderOptions } from './schema';
+import type { NormalizedLibraryOptions, PackageJsonData, SingleBuildState } from './types';
 
 /**
  * Executes the library builder to compile, bundle, and package an Angular library into the Angular Package Format (APF).
@@ -275,6 +272,19 @@ async function* runWatchLoop(
       try {
         const packageJson = await loadPackageJson(packageJsonPath);
         options.packageJson = packageJson;
+        if (!packageJson.name) {
+          throw new Error(`The package.json at '${packageJsonPath}' must contain a 'name'.`);
+        }
+        options.packageName = packageJson.name;
+
+        updateWatchedEntryPoints(
+          packageJson,
+          options,
+          buildState,
+          allWatchedFiles,
+          packageJsonPath,
+        );
+
         hasPackageJsonChanges = true;
       } catch (error) {
         assertIsError(error);
@@ -290,7 +300,8 @@ async function* runWatchLoop(
 
     const hasSourceChanges =
       !buildState.singleProgramCache ||
-      Boolean(buildState.hasCompilationError) ||
+      buildState.hasCompilationError ||
+      buildState.hasEntryPointsChanges ||
       hasModifiedWatchedFile(changedFiles, allWatchedFiles, posixPackageJsonPath);
 
     if (

diff --git a/packages/angular/build/src/builders/library/options.ts b/packages/angular/build/src/builders/library/options.ts
@@ -14,66 +14,16 @@ import { normalizeAssetPatterns } from '../../utils';
 import { supportColor } from '../../utils/color';
 import { assertIsError } from '../../utils/error';
 import { normalizeCacheOptions } from '../../utils/normalize-cache';
-import { isSubDirectory, toPosixPath } from '../../utils/path';
+import { isSubDirectory } from '../../utils/path';
 import {
-  type PostcssConfiguration,
   generateSearchDirectories,
   getTailwindConfig,
   loadPostcssConfiguration,
 } from '../../utils/postcss-configuration';
 import { getProjectRootPaths } from '../../utils/project-metadata';
-import { type NormalizedEntryPoint, getEntryPointBundleName } from './pipeline/entry-points';
+import { normalizeEntryPoints } from './pipeline/entry-points';
 import type { Schema as LibraryBuilderOptions } from './schema';
-
-export type { NormalizedEntryPoint } from './pipeline/entry-points';
-
-export interface PackageJsonData {
-  name: string;
-  version?: string;
-  type?: string;
-  main?: string;
-  module?: string;
-  typings?: string;
-  types?: string;
-  sideEffects?: boolean | string[];
-  exports?: string | Record<string, unknown>;
-  scripts?: Record<string, string>;
-  workspaces?: unknown;
-  dependencies?: Record<string, string>;
-  optionalDependencies?: Record<string, string>;
-  peerDependencies?: Record<string, string>;
-  peerDependenciesMeta?: Record<string, { optional?: boolean }>;
-  [key: string]: unknown;
-}
-
-export interface NormalizedLibraryOptions {
-  workspaceRoot: string;
-  projectRoot: string;
-  packageName: string;
-  packageJson: PackageJsonData;
-  outputPath: string;
-  deleteOutputPath: boolean;
-  packageJsonPath: string;
-  tsConfigPath: string;
-  entryPoints: Map<string, NormalizedEntryPoint>;
-  inlineStyleLanguage: 'css' | 'less' | 'sass' | 'scss';
-  styleIncludePaths: string[];
-  sass?: StylesheetPluginsass;
-  assets: ReturnType<typeof normalizeAssetPatterns>;
-  compilationMode: 'partial' | 'full';
-  declarationMap: boolean;
-  allowedNonPeerDependencies: RegExp[];
-  keepLifecycleScripts: boolean;
-  watch: boolean;
-  poll?: number;
-  preserveSymlinks: boolean;
-  progress: boolean;
-  clearScreen?: boolean;
-  cacheOptions: ReturnType<typeof normalizeCacheOptions>;
-  postcssConfiguration?: { config: PostcssConfiguration; configPath: string };
-  tailwindConfiguration?: { file: string; package: string };
-  colors: boolean;
-}
+import type { NormalizedLibraryOptions, PackageJsonData } from './types';
 
 export async function normalizeLibraryOptions(
   context: BuilderContext,
@@ -217,147 +167,3 @@ export async function normalizeLibraryOptions(
     tailwindConfiguration,
   };
 }
-
-/**
- * Normalizes a single entry point specification.
- *
- * @param key The entry point key from package.json exports (e.g. '.' or './testing').
- * @param posixKey Normalized POSIX key without trailing slashes.
- * @param isPrimary Whether this is the primary entry point.
- * @param targetPath The relative file path string from exports.
- * @param projectRoot The library project root directory.
- * @param packageName The root package name (e.g. `@my/lib`).
- * @returns The normalized entry point descriptor.
- */
-function normalizeEntryPoint(
-  key: string,
-  posixKey: string,
-  isPrimary: boolean,
-  targetPath: string,
-  projectRoot: string,
-  packageName: string,
-): NormalizedEntryPoint {
-  const name = isPrimary
-    ? '.'
-    : posixKey[0] === '.' && posixKey[1] === '/'
-      ? posixKey.slice(2)
-      : posixKey;
-
-  if (name !== '.' && (path.posix.isAbsolute(name) || name.includes('..'))) {
-    throw new Error(
-      `Invalid entry point key '${key}'. Entry point keys must be relative subpaths without '..' (e.g. './testing').`,
-    );
-  }
-
-  const subpath = isPrimary ? '.' : `./${name}`;
-  const displayName = isPrimary ? packageName : `${packageName}/${name}`;
-  const bundleName = getEntryPointBundleName(packageName, name);
-
-  const entryFilePath = path.resolve(projectRoot, targetPath);
-
-  if (!/(?<!\.d)\.(?:ts|mts)$/.test(entryFilePath)) {
-    throw new Error(
-      `Entry point '${key}' file path must be a TypeScript file ('.ts' or '.mts'): '${entryFilePath}'.`,
-    );
-  }
-
-  return {
-    subpath,
-    name,
-    displayName,
-    bundleName,
-    entryFilePath,
-    isPrimary,
-  };
-}
-
-/**
- * Normalizes all entry points from the library's `package.json` `exports` field.
- *
- * @param rawExports The `exports` field from `package.json`.
- * @param projectRoot The library project root directory.
- * @param packageJsonPath Path to `package.json` for error reporting.
- * @param packageName The root package name (e.g. `@my/lib`).
- * @returns A Map of normalized entry points keyed by name.
- */
-function normalizeEntryPoints(
-  rawExports: PackageJsonData['exports'],
-  projectRoot: string,
-  packageJsonPath: string,
-  packageName: string,
-): Map<string, NormalizedEntryPoint> {
-  if (!rawExports || (typeof rawExports !== 'string' && typeof rawExports !== 'object')) {
-    throw new Error(
-      `The 'package.json' at '${packageJsonPath}' must contain an 'exports' field defining the primary entry point ('.').`,
-    );
-  }
-
-  const exportsRecord = typeof rawExports === 'string' ? { '.': rawExports } : rawExports;
-
-  const entryPoints = new Map<string, NormalizedEntryPoint>();
-  let hasPrimary = false;
-
-  for (const [key, value] of Object.entries(exportsRecord)) {
-    let target: string | undefined;
-
-    if (typeof value === 'string') {
-      target = value;
-    } else if (
-      typeof value === 'object' &&
-      value !== null &&
-      !Array.isArray(value) &&
-      typeof (value as Record<string, unknown>)['default'] === 'string'
-    ) {
-      target = (value as Record<string, unknown>)['default'] as string;
-    }
-
-    const posixKey = toPosixPath(key).replace(/\/+$/, '');
-    const isPrimary = posixKey === '.' || posixKey === '';
-
-    if (!target) {
-      if (isPrimary) {
-        throw new Error(
-          `The primary entry point '.' in '${packageJsonPath}' must specify a string path ` +
-            `or a 'default' condition pointing to a TypeScript file.`,
-        );
-      }
-
-      // Non-JS/TS conditional export (e.g., sass/style-only subpath); preserve in package.json without compiling.
-      continue;
-    }
-
-    if (!isPrimary && !/\.m?ts$/.test(target)) {
-      // Static asset, stylesheet, or package.json export; preserve in package.json without compiling.
-      continue;
-    }
-
-    const entryPoint = normalizeEntryPoint(
-      key,
-      posixKey,
-      isPrimary,
-      target,
-      projectRoot,
-      packageName,
-    );
-
-    if (entryPoints.has(entryPoint.name)) {
-      throw new Error(
-        `Duplicate entry point detected: '${key}' resolves to the same name ('${entryPoint.name}') as an existing entry point.`,
-      );
-    }
-
-    entryPoints.set(entryPoint.name, entryPoint);
-
-    if (entryPoint.isPrimary) {
-      hasPrimary = true;
-    }
-  }
-
-  if (!hasPrimary) {
-    throw new Error(
-      `The 'exports' field in '${packageJsonPath}' must contain a primary entry point with key '.'.`,
-    );
-  }
-
-  return entryPoints;
-}
diff --git a/packages/angular/build/src/builders/library/pipeline/assets.ts b/packages/angular/build/src/builders/library/pipeline/assets.ts
@@ -11,7 +11,7 @@ import path from 'node:path';
 import picomatch from 'picomatch';
 import { toPosixPath } from '../../../utils/path';
 import { DEFAULT_ASSET_IGNORE, resolveAssets } from '../../../utils/resolve-assets';
-import type { NormalizedLibraryOptions } from '../options';
+import type { NormalizedLibraryOptions } from '../types';
 import { type DiskOutputFile, createDiskOutputFile } from './utils';
 
 /**

diff --git a/packages/angular/build/src/builders/library/pipeline/build-action.ts b/packages/angular/build/src/builders/library/pipeline/build-action.ts
@@ -11,28 +11,14 @@ import { constants, copyFile, mkdir, writeFile } from 'node:fs/promises';
 import path from 'node:path';
 import { emitFilesToDisk } from '../../../tools/esbuild/utils';
 import { toPosixPath } from '../../../utils/path';
-import type { NormalizedLibraryOptions } from '../options';
+import type { NormalizedLibraryOptions, SingleBuildState } from '../types';
 import { collectAssetsToEmit } from './assets';
-import { type BundleEntryPointInput, type BundleResult, bundleEntryPoints } from './bundler';
-import { type SingleProgramCache, compileLibrary } from './compilation';
+import { type BundleEntryPointInput, bundleEntryPoints } from './bundler';
+import { compileLibrary } from './compilation';
 import { generatePackageManifests } from './package-manifests';
 import type { createComponentStylesheetBundlerForLibrary } from './stylesheet-bundler';
 import type { OutputFile } from './utils';
 
-/**
- * State preserved across incremental builds in watch mode.
- */
-export interface SingleBuildState {
-  singleProgramCache?: SingleProgramCache;
-  previousBundleResults: Map<string, BundleResult>;
-  pendingChangedEsmFiles: Set<string>;
-  pendingChangedDtsFiles: Set<string>;
-  hasCompilationError?: boolean;
-  hasEmittedManifests?: boolean;
-  hasEmittedAssets?: boolean;
-  directoryExists: Set<string>;
-}
-
 /**
  * Creates a fresh {@link SingleBuildState} instance.
  */
@@ -86,7 +72,8 @@ export async function buildAction(actionContext: BuildActionContext): Promise<vo
   const shouldCompileEntryPoints =
     !modifiedFiles ||
     !buildState.singleProgramCache ||
-    Boolean(buildState.hasCompilationError) ||
+    buildState.hasCompilationError ||
+    buildState.hasEntryPointsChanges ||
     pendingChangedEsmFiles.size > 0 ||
     pendingChangedDtsFiles.size > 0 ||
     hasModifiedWatchedFile(modifiedFiles, allWatchedFiles, posixPackageJsonPath);
@@ -100,6 +87,7 @@ export async function buildAction(actionContext: BuildActionContext): Promise<vo
 
   if (shouldCompileEntryPoints) {
     buildState.hasCompilationError = true;
+    buildState.hasEntryPointsChanges = false;
 
     const {
       esmFiles,

diff --git a/packages/angular/build/src/builders/library/pipeline/bundler.ts b/packages/angular/build/src/builders/library/pipeline/bundler.ts
@@ -17,25 +17,14 @@ import {
 } from 'rolldown';
 import { dts } from 'rolldown-plugin-dts';
 import { toPosixPath } from '../../../utils/path';
-import type { NormalizedEntryPoint, NormalizedLibraryOptions } from '../options';
+import type { BundleResult, NormalizedEntryPoint, NormalizedLibraryOptions } from '../types';
 import {
   FESM_OUTPUT_DIR,
   type MemoryOutputFile,
   TYPES_OUTPUT_DIR,
   createMemoryOutputFile,
 } from './utils';
 
-/**
- * Cached module ID sets for a bundled entry point.
- */
-export interface BundleResult {
-  /** Exact set of virtual ESM module IDs bundled into this entry point. */
-  esmModuleIds: ReadonlySet<string>;
-
-  /** Exact set of virtual DTS module IDs bundled into this entry point. */
-  dtsModuleIds: ReadonlySet<string>;
-}
-
 /**
  * Output of the entry point bundling process.
  */

diff --git a/packages/angular/build/src/builders/library/pipeline/compilation.ts b/packages/angular/build/src/builders/library/pipeline/compilation.ts
@@ -15,28 +15,11 @@ import {
 import type { ComponentStylesheetBundler } from '../../../tools/esbuild/angular/component-stylesheets';
 import { useTypeChecking } from '../../../utils/environment-options';
 import { toPosixPath } from '../../../utils/path';
-import type { NormalizedEntryPoint, NormalizedLibraryOptions } from '../options';
+import type { NormalizedEntryPoint, NormalizedLibraryOptions, SingleProgramCache } from '../types';
 import { isDeclarationFile, isDeclarationSourceMapFile } from './utils';
 
 const EMITTED_EXTENSIONS = ['.js', '.mjs', '.cjs', '.d.ts', '.d.mts', '.d.cts'];
 
-/**
- * Cached state for the single unified library compilation.
- */
-export interface SingleProgramCache {
-  /** The active Angular compilation instance. */
-  readonly compilationInstance: AngularCompilation;
-
-  /** In-memory map of emitted JavaScript files keyed by relative output path. */
-  readonly esmFiles: Map<string, string>;
-
-  /** In-memory map of emitted TypeScript declaration files keyed by relative output path. */
-  readonly dtsFiles: Map<string, string>;
-
-  /** Set of file paths that failed during stylesheet bundling or compilation. */
-  readonly failedFiles?: ReadonlySet<string>;
-}
-
 /**
  * Output of the unified library compilation step.
  */