feat(compiler-cli): export tooling definitions (#29929)

PR Close #29929

packages/compiler-cli/index.ts

@@ -17,6 +17,7 @@ export * from './src/transformers/api';
 export * from './src/transformers/entry_points';
 
 export * from './src/perform_compile';
+export * from './src/tooling';
 
 // TODO(tbosch): remove this once cli 1.5 is fully released,
 // and usages in G3 are changed to `CompilerOptions`.

packages/compiler-cli/src/tooling.ts

@@ -0,0 +1,22 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/**
+ * @module
+ * @description
+ * Tooling support helpers.
+ */
+
+/**
+ * Known values for global variables in `@angular/core` that Terser should set using
+ * https://github.com/terser-js/terser#conditional-compilation
+ */
+export const GLOBAL_DEFS_FOR_TERSER = {
+  ngDevMode: false,
+  ngI18nClosureMode: false,
+};

packages/core/src/util/ng_dev_mode.ts

@@ -83,8 +83,7 @@ export function ngDevModeResetPerfCounters(): NgDevModePerfCounters {
  * set `ngDevMode == false` we should be helping the developer by providing
  * as much early warning and errors as possible.
  *
- * NOTE: changes to the `ngDevMode` name must be synced with the CLI and
- * possibly other third party tooling. Check with them before altering it.
+ * NOTE: changes to the `ngDevMode` name must be synced with `compiler-cli/src/tooling.ts`.
  */
 if (typeof ngDevMode === 'undefined' || ngDevMode) {
   ngDevModeResetPerfCounters();

packages/core/src/util/ng_i18n_closure_mode.ts

@@ -13,8 +13,7 @@ declare global {
 }
 
 /**
- * NOTE: changes to the `ngI18nClosureMode` name must be synced with the CLI and
- * possibly other third party tooling. Check with them before altering it.
+ * NOTE: changes to the `ngI18nClosureMode` name must be synced with `compiler-cli/src/tooling.ts`.
  */
 if (typeof ngI18nClosureMode === 'undefined') {
   // Make sure to refer to ngI18nClosureMode as ['ngI18nClosureMode'] for closure.