From 3deb68f2fad62c92725bf05a301397c282129246 Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Mon, 28 Sep 2026 12:27:45 -0400
Subject: [PATCH 1/2] perf(@angular/build): avoid loading compiler-cli and
 typescript in js transform worker

Previously, `OxcLinker` imported `ConsoleLogger` and `LogLevel` directly from
`@angular/compiler-cli`. Even though `@angular/compiler-cli/linker` is an isolated,
lightweight runtime (depending only on `semver` and `convert-source-map`), resolving
the main `@angular/compiler-cli` entry point (`bundles/index.js`) eagerly evaluated
the full `ngtsc` compiler toolchain and required the 10 MB `typescript.js` bundle at
the top level.

As a result, every worker isolate in the JavaScript transformer pool unnecessarily loaded
TypeScript and 50+ compiler modules upon bootstrap, incurring ~150 ms of startup CPU latency
and allocating ~12 MB of heap per worker thread.
---
 .../src/tools/angular/linker/oxc-linker.ts    | 23 +++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/packages/angular/build/src/tools/angular/linker/oxc-linker.ts b/packages/angular/build/src/tools/angular/linker/oxc-linker.ts
index 26133a6b5611..90cd1ea075ef 100644
--- a/packages/angular/build/src/tools/angular/linker/oxc-linker.ts
+++ b/packages/angular/build/src/tools/angular/linker/oxc-linker.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { ConsoleLogger, LogLevel } from '@angular/compiler-cli';
+import type { Logger } from '@angular/compiler-cli';
 import { type DeclarationScope, FileLinker, LinkerEnvironment } from '@angular/compiler-cli/linker';
 import type {
   AbsoluteFsPath,
@@ -45,7 +45,23 @@ const noopFileSystem: ReadonlyFileSystem = {
   relative: (_from: string, to: string) => to,
 } as unknown as ReadonlyFileSystem;
 
-let SHARED_LOGGER: ConsoleLogger;
+const defaultLogger: Logger = {
+  level: 1, // LogLevel.info
+  debug() {},
+  info(...args: string[]) {
+    // eslint-disable-next-line no-console
+    console.info(...args);
+  },
+  warn(...args: string[]) {
+    // eslint-disable-next-line no-console
+    console.warn(...args);
+  },
+  error(...args: string[]) {
+    // eslint-disable-next-line no-console
+    console.error(...args);
+  },
+};
+
 let SHARED_AST_HOST: OxcAstHost;
 let SHARED_DECLARATION_SCOPE: InlineDeclarationScope;
 
@@ -56,14 +72,13 @@ export class OxcLinker {
   readonly #fileLinker: FileLinker<unknown, string, unknown, string | undefined>;
 
   constructor(filename: string, code: string, jit = false) {
-    SHARED_LOGGER ??= new ConsoleLogger(LogLevel.info);
     SHARED_AST_HOST ??= new OxcAstHost();
     SHARED_DECLARATION_SCOPE ??= new InlineDeclarationScope();
 
     const astFactory = new StringAstFactory(code);
     const linkerEnvironment = LinkerEnvironment.create(
       noopFileSystem,
-      SHARED_LOGGER,
+      defaultLogger,
       SHARED_AST_HOST,
       astFactory,
       { linkerJitMode: jit, sourceMapping: false },

From 0594016006fd9db08fa8b916d97ae90a72a01f97 Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Mon, 28 Sep 2026 12:36:16 -0400
Subject: [PATCH 2/2] fixup! perf(@angular/build): avoid loading compiler-cli
 and typescript in js transform worker

---
 .../src/tools/angular/linker/oxc-linker.ts    | 25 +++++++++++++------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/packages/angular/build/src/tools/angular/linker/oxc-linker.ts b/packages/angular/build/src/tools/angular/linker/oxc-linker.ts
index 90cd1ea075ef..8870fe1cc7da 100644
--- a/packages/angular/build/src/tools/angular/linker/oxc-linker.ts
+++ b/packages/angular/build/src/tools/angular/linker/oxc-linker.ts
@@ -47,18 +47,29 @@ const noopFileSystem: ReadonlyFileSystem = {
 
 const defaultLogger: Logger = {
   level: 1, // LogLevel.info
-  debug() {},
+  debug(...args: string[]) {
+    if (this.level <= 0) {
+      // eslint-disable-next-line no-console
+      console.debug(...args);
+    }
+  },
   info(...args: string[]) {
-    // eslint-disable-next-line no-console
-    console.info(...args);
+    if (this.level <= 1) {
+      // eslint-disable-next-line no-console
+      console.info(...args);
+    }
   },
   warn(...args: string[]) {
-    // eslint-disable-next-line no-console
-    console.warn(...args);
+    if (this.level <= 2) {
+      // eslint-disable-next-line no-console
+      console.warn(...args);
+    }
   },
   error(...args: string[]) {
-    // eslint-disable-next-line no-console
-    console.error(...args);
+    if (this.level <= 3) {
+      // eslint-disable-next-line no-console
+      console.error(...args);
+    }
   },
 };