fix(@schematics/angular): add experimental message when using standal…

…one application schematic.

This commit adds a warning when using `ng new --standalone` and `ng generate app --standalone`.

packages/schematics/angular/application/index.ts

@@ -33,10 +33,17 @@ import { Builders, ProjectType } from '../utility/workspace-models';
 import { Schema as ApplicationOptions, Style } from './schema';
 
 export default function (options: ApplicationOptions): Rule {
- return async (host: Tree) => {
+ return async (host: Tree, context: SchematicContext) => {
  const { appDir, appRootSelector, componentOptions, folderName, sourceDir } =
  await getAppOptions(host, options);
 
+ if (options.standalone) {
+ context.logger.warn(
+ 'Standalone application structure is new and not yet supported by many existing' +
+ ` 'ng add' and 'ng update' integrations with community libraries.`,
+ );
+ }
+
  return chain([
  addAppToWorkspaceFile(options, appDir, folderName),
  options.standalone