diff --git a/etc/api/angular_devkit/build_optimizer/src/_golden-api.d.ts b/etc/api/angular_devkit/build_optimizer/src/_golden-api.d.ts
index efd778ab0f..c545afc96c 100644
--- a/etc/api/angular_devkit/build_optimizer/src/_golden-api.d.ts
+++ b/etc/api/angular_devkit/build_optimizer/src/_golden-api.d.ts
@@ -16,10 +16,4 @@ export declare function getScrubFileTransformerForCore(program: ts.Program): ts.
 
 export declare function getWrapEnumsTransformer(): ts.TransformerFactory<ts.SourceFile>;
 
-export declare function testImportTslib(content: string): boolean;
-
-export declare function testPrefixClasses(content: string): boolean;
-
-export declare function testScrubFile(content: string): boolean;
-
 export declare function transformJavascript(options: TransformJavascriptOptions): TransformJavascriptOutput;
diff --git a/packages/angular_devkit/build_optimizer/src/index.ts b/packages/angular_devkit/build_optimizer/src/index.ts
index 56f62c1f4b..78ea03851f 100644
--- a/packages/angular_devkit/build_optimizer/src/index.ts
+++ b/packages/angular_devkit/build_optimizer/src/index.ts
@@ -11,12 +11,11 @@ export { buildOptimizer } from './build-optimizer/build-optimizer';
 export { transformJavascript } from './helpers/transform-javascript';
 
 export { getFoldFileTransformer } from './transforms/class-fold';
-export { getImportTslibTransformer, testImportTslib } from './transforms/import-tslib';
-export { getPrefixClassesTransformer, testPrefixClasses } from './transforms/prefix-classes';
+export { getImportTslibTransformer } from './transforms/import-tslib';
+export { getPrefixClassesTransformer } from './transforms/prefix-classes';
 export { getPrefixFunctionsTransformer } from './transforms/prefix-functions';
 export {
   getScrubFileTransformer,
   getScrubFileTransformerForCore,
-  testScrubFile,
 } from './transforms/scrub-file';
 export { getWrapEnumsTransformer } from './transforms/wrap-enums';