fix(@angular/cli): Use the app default prefix when generating

fixes #7522

packages/@angular/cli/commands/generate.ts

@@ -145,6 +145,12 @@ export default Command.extend({
     const cwd = this.project.root;
     const schematicName = rawArgs[0];
 
+    if (schematicName === 'component' || schematicName === 'directive') {
+      if (commandOptions.prefix === undefined) {
+        commandOptions.prefix = appConfig.prefix;
+      }
+    }
+
     const SchematicRunTask = require('../tasks/schematic-run').default;
     const schematicRunTask = new SchematicRunTask({
       ui: this.ui,

tests/e2e/tests/generate/component/component-prefix.ts

@@ -0,0 +1,21 @@
+import {join} from 'path';
+import {ng} from '../../../utils/process';
+import {expectFileToMatch} from '../../../utils/fs';
+import { updateJsonFile } from '../../../utils/project';
+
+
+export default function() {
+  const componentDir = join('src', 'app', 'test-component');
+
+  return Promise.resolve()
+    .then(() => updateJsonFile('.angular-cli.json', configJson => {
+      const app = configJson['apps'][0];
+      app['prefix'] = 'pre';
+    }))
+    .then(() => ng('generate', 'component', 'test-component'))
+    .then(() => expectFileToMatch(join(componentDir, 'test-component.component.ts'),
+      /selector: 'pre-/))
+
+    // Try to run the unit tests.
+    .then(() => ng('test', '--single-run'));
+}

tests/e2e/tests/generate/directive/directive-prefix.ts

@@ -0,0 +1,21 @@
+import {join} from 'path';
+import {ng} from '../../../utils/process';
+import {expectFileToMatch} from '../../../utils/fs';
+import { updateJsonFile } from '../../../utils/project';
+
+
+export default function() {
+  const directiveDir = join('src', 'app');
+
+  return Promise.resolve()
+    .then(() => updateJsonFile('.angular-cli.json', configJson => {
+      const app = configJson['apps'][0];
+      app['prefix'] = 'pre';
+    }))
+    .then(() => ng('generate', 'directive', 'test-directive'))
+    .then(() => expectFileToMatch(join(directiveDir, 'test-directive.directive.ts'),
+      /selector: '\[pre/))
+
+    // Try to run the unit tests.
+    .then(() => ng('test', '--single-run'));
+}