feat(@schematics/angular): install packages when creating a new application

Fixes #12719

Author: alan-agius4

packages/schematics/angular/application/index.ts

@@ -22,6 +22,7 @@ import {
   template,
   url,
 } from '@angular-devkit/schematics';
+import { NodePackageInstallTask } from '@angular-devkit/schematics/tasks';
 import { Schema as E2eOptions } from '../e2e/schema';
 import {
   addProjectToWorkspace,
@@ -63,8 +64,8 @@ import { Schema as ApplicationOptions } from './schema';
 //   );
 // }
 
-function addDependenciesToPackageJson() {
-  return (host: Tree) => {
+function addDependenciesToPackageJson(options: ApplicationOptions) {
+  return (host: Tree, context: SchematicContext) => {
     [
       {
         type: NodeDependencyType.Dev,
@@ -83,6 +84,10 @@ function addDependenciesToPackageJson() {
       },
     ].forEach(dependency => addPackageJsonDependency(host, dependency));
 
+    if (!options.skipInstall) {
+      context.addTask(new NodePackageInstallTask());
+    }
+
     return host;
   };
 }
@@ -299,7 +304,6 @@ export default function (options: ApplicationOptions): Rule {
 
     return chain([
       addAppToWorkspaceFile(options, workspace),
-      options.skipPackageJson ? noop() : addDependenciesToPackageJson(),
       mergeWith(
         apply(url('./files/src'), [
           options.minimal ? filter(minimalPathFilter) : noop(),
@@ -369,6 +373,7 @@ export default function (options: ApplicationOptions): Rule {
           move(sourceDir),
         ]), MergeStrategy.Overwrite),
       schematic('e2e', e2eOptions),
+      options.skipPackageJson ? noop() : addDependenciesToPackageJson(options),
     ]);
   };
 }

packages/schematics/angular/application/schema.json

@@ -72,6 +72,11 @@
       "description": "Create a barebones project without any testing frameworks",
       "type": "boolean",
       "default": false
+    },
+    "skipInstall": {
+      "description": "Skip installing dependency packages.",
+      "type": "boolean",
+      "default": false
     }
   },
   "required": [

packages/schematics/angular/ng-new/index.ts

@@ -55,6 +55,8 @@ export default function (options: NgNewOptions): Rule {
     style: options.style,
     skipTests: options.skipTests,
     skipPackageJson: false,
+    // always 'skipInstall' here, so that we do it after the move
+    skipInstall: true,
   };
 
   return chain([