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

PR Close #29929

integration/terser/.gitignore

@@ -0,0 +1 @@
+core.min.js

integration/terser/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "terser",
+  "version": "0.0.0",
+  "scripts": {
+    "test": "node test.js"
+  },
+  "private": true,
+  "dependencies": {
+    "@angular/core": "file:../../dist/packages-dist/core",
+    "@angular/compiler": "file:../../dist/packages-dist/compiler",
+    "@angular/compiler-cli": "file:../../dist/packages-dist/compiler-cli",
+    "rxjs": "file:../../node_modules/rxjs",
+    "terser": "3.17.0",
+    "zone.js": "file:../../node_modules/zone.js"
+  }
+}

integration/terser/test.js

@@ -0,0 +1,25 @@
+const readFileSync = require('fs').readFileSync;
+const writeFileSync = require('fs').writeFileSync;
+const resolve = require('path').resolve;
+const Terser = require('terser');
+const GLOBAL_DEFS_FOR_TERSER = require('@angular/compiler-cli').GLOBAL_DEFS_FOR_TERSER;
+
+const outputPath = resolve(__dirname, './core.min.js');
+const pathToCoreFesm5 = resolve(__dirname, './node_modules/@angular/core/fesm5/core.js');
+const coreFesm5Content = readFileSync(pathToCoreFesm5, 'utf8');
+// Ensure that Terser global_defs exported by compiler-cli work.
+const terserOpts = {
+  compress: {
+    module: true,
+    global_defs: GLOBAL_DEFS_FOR_TERSER
+  }
+};
+const result = Terser.minify(coreFesm5Content, terserOpts);
+writeFileSync(outputPath, result.code);
+
+for (const def of Object.keys(GLOBAL_DEFS_FOR_TERSER)) {
+  if (result.code.includes(def)) {
+    throw `'${def}' should have been removed from core bundle, but was still there.\n` +
+      `See output at ${outputPath}.`;
+  }
+}

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.