fix(compiler): return enableIvy true when using `readConfiguration` (#32234)

PR Close #32234

packages/compiler-cli/src/perform_compile.ts

@@ -120,10 +120,11 @@ export function calcProjectFileAndBasePath(project: string):
 export function createNgCompilerOptions(
     basePath: string, config: any, tsOptions: ts.CompilerOptions): api.CompilerOptions {
   // enableIvy `ngtsc` is an alias for `true`.
-  if (config.angularCompilerOptions && config.angularCompilerOptions.enableIvy === 'ngtsc') {
-    config.angularCompilerOptions.enableIvy = true;
-  }
-  return {...tsOptions, ...config.angularCompilerOptions, genDir: basePath, basePath};
+  const {angularCompilerOptions = {}} = config;
+  const {enableIvy} = angularCompilerOptions;
+  angularCompilerOptions.enableIvy = enableIvy !== false && enableIvy !== 'tsc';
+
+  return {...tsOptions, ...angularCompilerOptions, genDir: basePath, basePath};
 }
 
 export function readConfiguration(

packages/compiler-cli/test/perform_compile_spec.ts

@@ -55,4 +55,26 @@ describe('perform_compile', () => {
     expect(options.skipMetadataEmit).toBe(true);
   });
 
+  it(`should return 'enableIvy: true' when enableIvy is not defined in "angularCompilerOptions"`,
+     () => {
+       writeSomeConfigs();
+       const {options} = readConfiguration(path.resolve(basePath, 'tsconfig-level-1.json'));
+       expect(options.enableIvy).toBe(true);
+     });
+
+  it(`should return 'enableIvy: false' when enableIvy is disabled in "angularCompilerOptions"`,
+     () => {
+       writeSomeConfigs();
+       support.writeFiles({
+         'tsconfig-level-3.json': `{
+          "angularCompilerOptions": {
+            "enableIvy": false
+          }
+        }
+      `,
+       });
+
+       const {options} = readConfiguration(path.resolve(basePath, 'tsconfig-level-1.json'));
+       expect(options.enableIvy).toBe(false);
+     });
 });