angular · clydin · Aug 14, 2026
diff --git a/packages/angular/build/src/tools/angular/angular-host.ts b/packages/angular/build/src/tools/angular/angular-host.ts
@@ -17,7 +17,6 @@ export type AngularCompilerHost = ng.CompilerHost;
 
 export interface AngularHostOptions {
   fileReplacements?: Record<string, string>;
-  sourceFileCache?: Map<string, ts.SourceFile>;
   modifiedFiles?: Set<string>;
   externalStylesheets?: Map<string, string>;
   transformStylesheet(
@@ -165,6 +164,7 @@ export function createAngularCompilerHost(
   compilerOptions: AngularCompilerOptions,
   hostOptions: AngularHostOptions,
   packageJsonCache: ts.PackageJsonInfoCache | undefined,
+  sourceFileCache?: Map<string, ts.SourceFile>,
 ): AngularCompilerHost {
   // Create TypeScript compiler host
   const host: AngularCompilerHost = typescript.createIncrementalCompilerHost(compilerOptions);
@@ -254,8 +254,8 @@ export function createAngularCompilerHost(
   }
 
   // Augment TypeScript Host with source file caching if provided
-  if (hostOptions.sourceFileCache) {
-    augmentHostWithCaching(host, hostOptions.sourceFileCache);
+  if (sourceFileCache) {
+    augmentHostWithCaching(host, sourceFileCache);
   }
 
   return host;

diff --git a/packages/angular/build/src/tools/angular/compilation/aot-compilation.ts b/packages/angular/build/src/tools/angular/compilation/aot-compilation.ts
@@ -11,6 +11,7 @@ import assert from 'node:assert';
 import { relative } from 'node:path';
 import ts from 'typescript';
 import { useTypeChecking } from '../../../utils/environment-options';
+import { toPosixPath } from '../../../utils/path';
 import { profileAsync, profileSync } from '../../esbuild/profiling';
 import {
   AngularHostOptions,
@@ -55,6 +56,7 @@ class AngularCompilationState {
 
 export class AotCompilation extends AngularCompilation {
   #state?: AngularCompilationState;
+  readonly #sourceFiles = new Map<string, ts.SourceFile>();
 
   constructor(private readonly browserOnlyBuild: boolean) {
     super();
@@ -97,27 +99,37 @@ export class AotCompilation extends AngularCompilation {
 
     let staleSourceFiles;
     let clearPackageJsonCache = false;
-    if (hostOptions.modifiedFiles && this.#state) {
+    if (hostOptions.modifiedFiles) {
       for (const modifiedFile of hostOptions.modifiedFiles) {
-        // Clear package.json cache if a node modules file was modified
-        if (!clearPackageJsonCache && modifiedFile.includes('node_modules')) {
-          clearPackageJsonCache = true;
-          packageJsonCache?.clear();
-        }
+        this.#sourceFiles.delete(toPosixPath(modifiedFile));
 
-        // Collect stale source files for HMR analysis of inline component resources
-        if (useHmr) {
-          const sourceFile = this.#state.typeScriptProgram.getSourceFile(modifiedFile);
-          if (sourceFile) {
-            staleSourceFiles ??= new Map<string, ts.SourceFile>();
-            staleSourceFiles.set(modifiedFile, sourceFile);
+        if (this.#state) {
+          // Clear package.json cache if a node modules file was modified
+          if (!clearPackageJsonCache && modifiedFile.includes('node_modules')) {
+            clearPackageJsonCache = true;
+            packageJsonCache?.clear();
+          }
+
+          // Collect stale source files for HMR analysis of inline component resources
+          if (useHmr) {
+            const sourceFile = this.#state.typeScriptProgram.getSourceFile(modifiedFile);
+            if (sourceFile) {
+              staleSourceFiles ??= new Map<string, ts.SourceFile>();
+              staleSourceFiles.set(modifiedFile, sourceFile);
+            }
           }
         }
       }
     }
 
     // Create Angular compiler host
-    const host = createAngularCompilerHost(ts, compilerOptions, hostOptions, packageJsonCache);
+    const host = createAngularCompilerHost(
+      ts,
+      compilerOptions,
+      hostOptions,
+      packageJsonCache,
+      this.#sourceFiles,
+    );
 
     // Create the Angular specific program that contains the Angular compiler
     const angularProgram = profileSync(
@@ -451,6 +463,12 @@ export class AotCompilation extends AngularCompilation {
 
     return emittedFiles.values();
   }
+
+  override async update(files: Set<string>): Promise<void> {
+    for (const file of files) {
+      this.#sourceFiles.delete(toPosixPath(file));
+    }
+  }
 }
 
 function findAffectedFiles(

diff --git a/packages/angular/build/src/tools/angular/compilation/jit-compilation.ts b/packages/angular/build/src/tools/angular/compilation/jit-compilation.ts
@@ -9,6 +9,7 @@
 import type * as ng from '@angular/compiler-cli';
 import assert from 'node:assert';
 import ts from 'typescript';
+import { toPosixPath } from '../../../utils/path';
 import { profileSync } from '../../esbuild/profiling';
 import { AngularHostOptions, createAngularCompilerHost } from '../angular-host';
 import { createJitResourceTransformer } from '../transformers/jit-resource-transformer';
@@ -33,6 +34,7 @@ class JitCompilationState {
 
 export class JitCompilation extends AngularCompilation {
   #state?: JitCompilationState;
+  readonly #sourceFiles = new Map<string, ts.SourceFile>();
 
   constructor(private readonly browserOnlyBuild: boolean) {
     super();
@@ -56,8 +58,20 @@ export class JitCompilation extends AngularCompilation {
     const compilerOptions =
       compilerOptionsTransformer?.(originalCompilerOptions) ?? originalCompilerOptions;
 
+    if (hostOptions.modifiedFiles) {
+      for (const modifiedFile of hostOptions.modifiedFiles) {
+        this.#sourceFiles.delete(toPosixPath(modifiedFile));
+      }
+    }
+
     // Create Angular compiler host
-    const host = createAngularCompilerHost(ts, compilerOptions, hostOptions, undefined);
+    const host = createAngularCompilerHost(
+      ts,
+      compilerOptions,
+      hostOptions,
+      undefined,
+      this.#sourceFiles,
+    );
 
     // Create the TypeScript Program
     const typeScriptProgram = profileSync('TS_CREATE_PROGRAM', () =>
@@ -70,10 +84,6 @@ export class JitCompilation extends AngularCompilation {
       ),
     );
 
-    const affectedFiles = profileSync('TS_FIND_AFFECTED', () =>
-      findAffectedFiles(typeScriptProgram),
-    );
-
     this.#state = new JitCompilationState(
       host,
       typeScriptProgram,
@@ -157,17 +167,10 @@ export class JitCompilation extends AngularCompilation {
 
     return emittedFiles;
   }
-}
-
-function findAffectedFiles(
-  builder: ts.EmitAndSemanticDiagnosticsBuilderProgram,
-): Set<ts.SourceFile> {
-  const affectedFiles = new Set<ts.SourceFile>();
 
-  let result;
-  while ((result = builder.getSemanticDiagnosticsOfNextAffectedFile())) {
-    affectedFiles.add(result.affected as ts.SourceFile);
+  override async update(files: Set<string>): Promise<void> {
+    for (const file of files) {
+      this.#sourceFiles.delete(toPosixPath(file));
+    }
   }
-
-  return affectedFiles;
 }
diff --git a/packages/angular/build/src/tools/angular/compilation/parallel-worker.ts b/packages/angular/build/src/tools/angular/compilation/parallel-worker.ts
@@ -11,7 +11,6 @@ import assert from 'node:assert';
 import { randomUUID } from 'node:crypto';
 import { type MessagePort, receiveMessageOnPort } from 'node:worker_threads';
 import { initializeHash } from '../../../utils/hash';
-import { SourceFileCache } from '../../esbuild/angular/source-file-cache';
 import { getAndClearCumulativeDurations } from '../../esbuild/profiling';
 import type {
   AngularCompilation,
@@ -35,9 +34,12 @@ export interface InitRequest {
 
 let compilation: AngularCompilation | undefined;
 
-const sourceFileCache = new SourceFileCache();
+const modifiedFiles = new Set<string>();
 
 export async function initialize(request: InitRequest): Promise<AngularCompilationResult> {
+  const currentModifiedFiles = new Set(modifiedFiles);
+  modifiedFiles.clear();
+
   await initializeHash();
   compilation ??= request.jit
     ? new JitCompilation(request.browserOnlyBuild)
@@ -62,8 +64,7 @@ export async function initialize(request: InitRequest): Promise<AngularCompilati
     request.tsconfig,
     {
       fileReplacements: request.fileReplacements,
-      sourceFileCache,
-      modifiedFiles: sourceFileCache.modifiedFiles,
+      modifiedFiles: currentModifiedFiles,
       transformStylesheet(data, containingFile, stylesheetFile, order, className) {
         const requestId = randomUUID();
         const resultPromise = new Promise<string>((resolve, reject) =>
@@ -151,6 +152,9 @@ export async function emit() {
   return [...files];
 }
 
-export function update(files: Set<string>): void {
-  sourceFileCache.invalidate(files);
+export async function update(files: Set<string>): Promise<void> {
+  for (const file of files) {
+    modifiedFiles.add(file);
+  }
+  await compilation?.update?.(files);
 }
diff --git a/packages/angular/build/src/tools/esbuild/angular/compiler-plugin.ts b/packages/angular/build/src/tools/esbuild/angular/compiler-plugin.ts
@@ -187,7 +187,6 @@ export function createCompilerPlugin(
         const hostOptions: AngularHostOptions = {
           fileReplacements: pluginOptions.fileReplacements,
           modifiedFiles,
-          sourceFileCache: pluginOptions.sourceFileCache,
           async transformStylesheet(data, containingFile, stylesheetFile, order, className) {
             let stylesheetResult;
             let resultSource = stylesheetFile ?? containingFile;

diff --git a/packages/angular/build/src/tools/esbuild/angular/source-file-cache.ts b/packages/angular/build/src/tools/esbuild/angular/source-file-cache.ts
@@ -6,32 +6,24 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { platform } from 'node:os';
 import * as path from 'node:path';
-import type ts from 'typescript';
 import { MemoryLoadResultCache } from '../load-result-cache';
 
-const USING_WINDOWS = platform() === 'win32';
-const WINDOWS_SEP_REGEXP = new RegExp(`\\${path.win32.sep}`, 'g');
-
-export class SourceFileCache extends Map<string, ts.SourceFile> {
+export class SourceFileCache {
   readonly modifiedFiles = new Set<string>();
   readonly typeScriptFileCache = new Map<string, string | Uint8Array>();
   readonly loadResultCache = new MemoryLoadResultCache();
 
   referencedFiles?: readonly string[];
 
-  constructor(readonly persistentCachePath?: string) {
-    super();
-  }
+  constructor(readonly persistentCachePath?: string) {}
 
   /**
    * Releases all cached content. The cached data is only needed for incremental
    * rebuilds and can include the emitted contents of every TypeScript file in the
    * program. The cache is repopulated if a build is performed after this is called.
    */
-  override clear(): void {
-    super.clear();
+  clear(): void {
     this.modifiedFiles.clear();
     this.typeScriptFileCache.clear();
     this.loadResultCache.clear();
@@ -50,13 +42,6 @@ export class SourceFileCache extends Map<string, ts.SourceFile> {
       file = path.normalize(file);
       invalid = this.loadResultCache.invalidate(file) || invalid;
       invalid = extraWatchFiles.has(file) || invalid;
-
-      // Normalize separators to allow matching TypeScript Host paths
-      if (USING_WINDOWS) {
-        file = file.replace(WINDOWS_SEP_REGEXP, path.posix.sep);
-      }
-
-      invalid = this.delete(file) || invalid;
       this.modifiedFiles.add(file);
     }