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,
+};