fix(compiler): remove TypeScript from linker (angular#61618)

alan-agius4 · thePunderWoman · commit e9fcbb8af12e · 2025-05-26T08:46:00.000Z
This commit removes the direct dependency on TypeScript within the linker, addressing a performance overhead that was adding between 500ms to 1s to compilation times for applications. The primary cause of this overhead was the linker's direct reliance on TypeScript's which was caused by importing from barrel files. While convenient, barrel files are detrimental to code splitting and code motion. They force the bundling of all exported modules, even if only a subset is actually used. By removing the usage of this barrel file and restructuring the imports to be more granular, we can avoid unnecessary TypeScript imports. Furthermore, TypeScript has now been changed to an optional peer dependency as using only the linker does not require TypeScript. PR Close angular#61618
diff --git a/.aspect/rules/external_repository_action_cache/npm_translate_lock_MzA5NzUwNzMx b/.aspect/rules/external_repository_action_cache/npm_translate_lock_MzA5NzUwNzMx
@@ -3,7 +3,7 @@
 # This file should be checked into version control along with the pnpm-lock.yaml file.
 .npmrc=-1406867100
 package.json=-1316846371
-packages/compiler-cli/package.json=1094415146
+packages/compiler-cli/package.json=-1344632265
 packages/compiler/package.json=1190056499
 pnpm-lock.yaml=1584116426
 pnpm-workspace.yaml=353334404
diff --git a/.bazelignore b/.bazelignore
@@ -24,6 +24,7 @@ integration/ng_elements/node_modules
 integration/ng_update/node_modules
 integration/ng_update_migrations/node_modules
 integration/ng-add-localize/node_modules
+integration/no_ts_linker/node_modules
 integration/nodenext_resolution/node_modules
 integration/platform-server/node_modules
 integration/platform-server-zoneless/node_modules
diff --git a/integration/no_ts_linker/BUILD.bazel b/integration/no_ts_linker/BUILD.bazel
@@ -0,0 +1,5 @@
+load("//integration:index.bzl", "ng_integration_test")
+
+ng_integration_test(
+    name = "test",
+)
diff --git a/integration/no_ts_linker/package.json b/integration/no_ts_linker/package.json
@@ -0,0 +1,16 @@
+{
+  "name": "angular-integration",
+  "description": "Assert that the linker has no dependency on TypeScript.",
+  "version": "0.0.0",
+  "license": "MIT",
+  "type": "module",
+  "dependencies": {
+    "@angular/compiler": "file:../../dist/packages-dist/compiler",
+    "@angular/compiler-cli": "file:../../dist/packages-dist/compiler-cli",
+    "@angular/core": "file:../../dist/packages-dist/core",
+    "rxjs": "file:../../node_modules/rxjs"
+  },
+  "scripts": {
+    "test": "node ./test.mjs"
+  }
+}
diff --git a/integration/no_ts_linker/test.mjs b/integration/no_ts_linker/test.mjs
@@ -0,0 +1,18 @@
+import assert from 'node:assert';
+
+(async () => {
+  // Verify that TypeScript is not installed.
+  await assert.rejects(
+    () => import('typescript'),
+    ({code, message}) => {
+      assert.strictEqual(code, 'ERR_MODULE_NOT_FOUND');
+      assert.match(message, new RegExp(`Cannot find package 'typescript'`));
+
+      return true;
+    },
+  );
+
+  // This validates that the linker has no dependency on TypeScript.
+  await import('@angular/compiler-cli/linker');
+  await import('@angular/compiler-cli/linker/babel');
+})();
diff --git a/packages/compiler-cli/linker/babel/src/ast/babel_ast_factory.ts b/packages/compiler-cli/linker/babel/src/ast/babel_ast_factory.ts
@@ -16,7 +16,7 @@ import {
   SourceMapRange,
   TemplateLiteral,
   VariableDeclarationType,
-} from '../../../../src/ngtsc/translator';
+} from '../../../../src/ngtsc/translator/src/api/ast_factory';
 
 /**
  * A Babel flavored implementation of the AstFactory.
diff --git a/packages/compiler-cli/linker/babel/src/babel_plugin.ts b/packages/compiler-cli/linker/babel/src/babel_plugin.ts
@@ -7,11 +7,11 @@
  */
 import {ConfigAPI, PluginObj} from '@babel/core';
 
-import {NodeJSFileSystem} from '../../../src/ngtsc/file_system';
 import {ConsoleLogger, LogLevel} from '../../../src/ngtsc/logging';
 import {LinkerOptions} from '../../src/file_linker/linker_options';
 
 import {createEs2015LinkerPlugin} from './es2015_linker_plugin';
+import {NodeJSFileSystem} from '../../../src/ngtsc/file_system/src/node_js_file_system';
 
 /**
  * This is the Babel plugin definition that is provided as a default export from the package, such
diff --git a/packages/compiler-cli/linker/babel/src/linker_plugin_options.ts b/packages/compiler-cli/linker/babel/src/linker_plugin_options.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 import {LinkerOptions} from '../..';
-import {ReadonlyFileSystem} from '../../../src/ngtsc/file_system';
+import {ReadonlyFileSystem} from '../../../src/ngtsc/file_system/src/types';
 import {Logger} from '../../../src/ngtsc/logging';
 
 export interface LinkerPluginOptions extends Partial<LinkerOptions> {
diff --git a/packages/compiler-cli/linker/src/file_linker/file_linker.ts b/packages/compiler-cli/linker/src/file_linker/file_linker.ts
@@ -7,14 +7,14 @@
  */
 import {R3PartialDeclaration} from '@angular/compiler';
 
-import {AbsoluteFsPath} from '../../../src/ngtsc/file_system';
 import {AstObject} from '../ast/ast_value';
 
 import {DeclarationScope} from './declaration_scope';
 import {EmitScope} from './emit_scopes/emit_scope';
 import {LocalEmitScope} from './emit_scopes/local_emit_scope';
 import {LinkerEnvironment} from './linker_environment';
 import {createLinkerMap, PartialLinkerSelector} from './partial_linkers/partial_linker_selector';
+import {AbsoluteFsPath} from '../../../src/ngtsc/file_system/src/types';
 
 export const NO_STATEMENTS: Readonly<any[]> = [] as const;
 
diff --git a/packages/compiler-cli/linker/src/file_linker/get_source_file.ts b/packages/compiler-cli/linker/src/file_linker/get_source_file.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import {AbsoluteFsPath} from '../../../src/ngtsc/file_system';
+import {AbsoluteFsPath} from '../../../src/ngtsc/file_system/src/types';
 import {SourceFile, SourceFileLoader} from '../../../src/ngtsc/sourcemaps';
 
 /**
diff --git a/packages/compiler-cli/linker/src/file_linker/linker_environment.ts b/packages/compiler-cli/linker/src/file_linker/linker_environment.ts
@@ -5,7 +5,7 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.dev/license
  */
-import {ReadonlyFileSystem} from '../../../src/ngtsc/file_system';
+import {ReadonlyFileSystem} from '../../../src/ngtsc/file_system/src/types';
 import {Logger} from '../../../src/ngtsc/logging';
 import {SourceFileLoader} from '../../../src/ngtsc/sourcemaps';
 import {AstFactory} from '../../../src/ngtsc/translator';
diff --git a/packages/compiler-cli/linker/src/file_linker/partial_linkers/partial_component_linker_1.ts b/packages/compiler-cli/linker/src/file_linker/partial_linkers/partial_component_linker_1.ts
@@ -33,7 +33,6 @@ import {
 } from '@angular/compiler';
 import semver from 'semver';
 
-import {AbsoluteFsPath} from '../../../../src/ngtsc/file_system';
 import {Range} from '../../ast/ast_host';
 import {AstObject, AstValue} from '../../ast/ast_value';
 import {FatalLinkerError} from '../../fatal_linker_error';
@@ -42,6 +41,7 @@ import {GetSourceFileFn} from '../get_source_file';
 import {toR3DirectiveMeta} from './partial_directive_linker_1';
 import {LinkedDefinition, PartialLinker} from './partial_linker';
 import {extractForwardRef, PLACEHOLDER_VERSION} from './util';
+import {AbsoluteFsPath} from '../../../../src/ngtsc/file_system/src/types';
 
 function makeDirectiveMetadata<TExpression>(
   directiveExpr: AstObject<R3DeclareDirectiveDependencyMetadata, TExpression>,
diff --git a/packages/compiler-cli/linker/src/file_linker/partial_linkers/partial_directive_linker_1.ts b/packages/compiler-cli/linker/src/file_linker/partial_linkers/partial_directive_linker_1.ts
@@ -26,13 +26,13 @@ import {
   R3QueryMetadata,
 } from '@angular/compiler';
 
-import {AbsoluteFsPath} from '../../../../src/ngtsc/file_system';
 import {Range} from '../../ast/ast_host';
 import {AstObject, AstValue} from '../../ast/ast_value';
 import {FatalLinkerError} from '../../fatal_linker_error';
 
 import {LinkedDefinition, PartialLinker} from './partial_linker';
 import {extractForwardRef, getDefaultStandaloneValue, wrapReference} from './util';
+import {AbsoluteFsPath} from '../../../../src/ngtsc/file_system/src/types';
 
 /**
  * A `PartialLinker` that is designed to process `ɵɵngDeclareDirective()` call expressions.
diff --git a/packages/compiler-cli/linker/src/file_linker/partial_linkers/partial_linker_selector.ts b/packages/compiler-cli/linker/src/file_linker/partial_linkers/partial_linker_selector.ts
@@ -7,7 +7,6 @@
  */
 import semver from 'semver';
 
-import {AbsoluteFsPath} from '../../../../src/ngtsc/file_system';
 import {Logger} from '../../../../src/ngtsc/logging';
 import {createGetSourceFile} from '../get_source_file';
 import {LinkerEnvironment} from '../linker_environment';
@@ -23,6 +22,7 @@ import {PartialLinker} from './partial_linker';
 import {PartialNgModuleLinkerVersion1} from './partial_ng_module_linker_1';
 import {PartialPipeLinkerVersion1} from './partial_pipe_linker_1';
 import {PLACEHOLDER_VERSION} from './util';
+import {AbsoluteFsPath} from '../../../../src/ngtsc/file_system/src/types';
 
 export const ɵɵngDeclareDirective = 'ɵɵngDeclareDirective';
 export const ɵɵngDeclareClassMetadata = 'ɵɵngDeclareClassMetadata';
diff --git a/packages/compiler-cli/linker/src/file_linker/translator.ts b/packages/compiler-cli/linker/src/file_linker/translator.ts
@@ -6,14 +6,13 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 import * as o from '@angular/compiler';
-
 import {
-  AstFactory,
-  Context,
   ExpressionTranslatorVisitor,
-  ImportGenerator,
   TranslatorOptions,
-} from '../../../src/ngtsc/translator';
+} from '../../../src/ngtsc/translator/src/translator';
+import {Context} from '../../../src/ngtsc/translator/src/context';
+import {ImportGenerator} from '../../../src/ngtsc/translator/src/api/import_generator';
+import {AstFactory} from '../../../src/ngtsc/translator/src/api/ast_factory';
 
 /**
  * Generic translator helper class, which exposes methods for translating expressions and
diff --git a/packages/compiler-cli/package.json b/packages/compiler-cli/package.json
@@ -55,6 +55,11 @@
     "@angular/compiler": "0.0.0-PLACEHOLDER",
     "typescript": ">=5.8 <5.9"
   },
+  "peerDependenciesMeta": {
+    "typescript": {
+      "optional": true
+    }
+  },
   "devDependencies": {
     "@angular/compiler": "workspace:*"
   },
diff --git a/packages/compiler-cli/src/ngtsc/translator/src/translator.ts b/packages/compiler-cli/src/ngtsc/translator/src/translator.ts
@@ -19,12 +19,12 @@ import {
 import {ImportGenerator} from './api/import_generator';
 import {Context} from './context';
 
-const UNARY_OPERATORS = new Map<o.UnaryOperator, UnaryOperator>([
+const UNARY_OPERATORS = /* @__PURE__ */ new Map<o.UnaryOperator, UnaryOperator>([
   [o.UnaryOperator.Minus, '-'],
   [o.UnaryOperator.Plus, '+'],
 ]);
 
-const BINARY_OPERATORS = new Map<o.BinaryOperator, BinaryOperator>([
+const BINARY_OPERATORS = /* @__PURE__ */ new Map<o.BinaryOperator, BinaryOperator>([
   [o.BinaryOperator.And, '&&'],
   [o.BinaryOperator.Bigger, '>'],
   [o.BinaryOperator.BiggerEquals, '>='],
diff --git a/packages/compiler-cli/src/ngtsc/translator/src/typescript_ast_factory.ts b/packages/compiler-cli/src/ngtsc/translator/src/typescript_ast_factory.ts
@@ -34,13 +34,13 @@ enum PureAnnotation {
   TERSER = '@__PURE__',
 }
 
-const UNARY_OPERATORS: Record<UnaryOperator, ts.PrefixUnaryOperator> = {
+const UNARY_OPERATORS: Record<UnaryOperator, ts.PrefixUnaryOperator> = /* @__PURE__ */ (() => ({
   '+': ts.SyntaxKind.PlusToken,
   '-': ts.SyntaxKind.MinusToken,
   '!': ts.SyntaxKind.ExclamationToken,
-};
+}))();
 
-const BINARY_OPERATORS: Record<BinaryOperator, ts.BinaryOperator> = {
+const BINARY_OPERATORS: Record<BinaryOperator, ts.BinaryOperator> = /* @__PURE__ */ (() => ({
   '&&': ts.SyntaxKind.AmpersandAmpersandToken,
   '>': ts.SyntaxKind.GreaterThanToken,
   '>=': ts.SyntaxKind.GreaterThanEqualsToken,
@@ -61,13 +61,13 @@ const BINARY_OPERATORS: Record<BinaryOperator, ts.BinaryOperator> = {
   '+': ts.SyntaxKind.PlusToken,
   '??': ts.SyntaxKind.QuestionQuestionToken,
   'in': ts.SyntaxKind.InKeyword,
-};
+}))();
 
-const VAR_TYPES: Record<VariableDeclarationType, ts.NodeFlags> = {
+const VAR_TYPES: Record<VariableDeclarationType, ts.NodeFlags> = /* @__PURE__ */ (() => ({
   'const': ts.NodeFlags.Const,
   'let': ts.NodeFlags.Let,
   'var': ts.NodeFlags.None,
-};
+}))();
 
 /**
  * A TypeScript flavoured implementation of the AstFactory.
