perf(core): add option to remove blank text nodes from compiled templates

packages/compiler-cli/src/transformers/api.ts

@@ -111,6 +111,10 @@ export interface CompilerOptions extends ts.CompilerOptions {
   i18nInFile?: string;
   // How to handle missing messages
   i18nInMissingTranslations?: 'error'|'warning'|'ignore';
+
+  // Whether to remove blank text nodes from compiled templates. It is `true` by default
+  // in Angular 5 and will be re-visited in Angular 6.
+  preserveWhitespaces?: boolean;
 }
 
 export interface ModuleFilenameResolver {

packages/compiler-cli/src/transformers/program.ts

@@ -347,6 +347,7 @@ function getAotCompilerOptions(options: CompilerOptions): AotCompilerOptions {
     i18nFormat: options.i18nInFormat || options.i18nOutFormat, translations, missingTranslation,
     enableLegacyTemplate: options.enableLegacyTemplate,
     enableSummariesForJit: true,
+    preserveWhitespaces: options.preserveWhitespaces,
   };
 }
 
@@ -480,4 +481,4 @@ function createProgramWithStubsHost(
     fileExists = (fileName: string) =>
         this.generatedFiles.has(fileName) || originalHost.fileExists(fileName);
   };
-}
+}