feat(@schematics/angular): add configuration files generation schematic

This commits add a schematic to generate Karma and Browserlist files which since version 15 are no longer generated by default. This schematic should be used to generate these files when further customisation is needed.

Usage
```
ng generate config karma
ng generate config browserlist
```

Closes #24294

packages/angular_devkit/build_angular/src/builders/karma/index.ts

@@ -96,7 +96,7 @@ export function execute(
 
       const karmaOptions: KarmaConfigOptions = options.karmaConfig
         ? {}
-        : getBuiltInKarmaConfig(karma, context.workspaceRoot, projectName);
+        : getBuiltInKarmaConfig(context.workspaceRoot, projectName);
 
       karmaOptions.singleRun = singleRun;
 
@@ -186,7 +186,6 @@ export function execute(
 }
 
 function getBuiltInKarmaConfig(
-  karma: typeof import('karma'),
   workspaceRoot: string,
   projectName: string,
 ): ConfigOptions & Record<string, unknown> {
@@ -197,6 +196,7 @@ function getBuiltInKarmaConfig(
 
   const workspaceRootRequire = createRequire(workspaceRoot + '/');
 
+  // Any changes to the config here need to be synced to: packages/schematics/angular/config/files/karma.conf.js.template
   return {
     basePath: '',
     frameworks: ['jasmine', '@angular-devkit/build-angular'],

packages/schematics/angular/collection.json

@@ -120,6 +120,11 @@
       "factory": "./environments",
       "schema": "./environments/schema.json",
       "description": "Generate project environment files."
+    },
+    "config": {
+      "factory": "./config",
+      "schema": "./config/schema.json",
+      "description": "Generates a configuration file."
     }
   }
 }

packages/schematics/angular/config/files/.browserslistrc.template

@@ -0,0 +1,16 @@
+# This file is used by the build system to adjust CSS and JS output to support the specified browsers below.
+# For additional information regarding the format and rule options, please see:
+# https://github.com/browserslist/browserslist#queries
+
+# For the full list of supported browsers by the Angular framework, please see:
+# https://angular.io/guide/browser-support
+
+# You can see what browsers were selected by your queries by running:
+#   npx browserslist
+
+last 1 Chrome version
+last 1 Firefox version
+last 2 Edge major versions
+last 2 Safari major versions
+last 2 iOS major versions
+Firefox ESR

packages/schematics/angular/config/files/karma.conf.js.template

@@ -0,0 +1,39 @@
+// Karma configuration file, see link for more information
+// https://karma-runner.github.io/1.0/config/configuration-file.html
+
+module.exports = function (config) {
+  config.set({
+    basePath: '',
+    frameworks: ['jasmine', '@angular-devkit/build-angular'],
+    plugins: [
+      require('karma-jasmine'),
+      require('karma-chrome-launcher'),
+      require('karma-jasmine-html-reporter'),
+      require('karma-coverage'),
+      require('@angular-devkit/build-angular/plugins/karma')
+    ],
+    client: {
+      jasmine: {
+        // you can add configuration options for Jasmine here
+        // the possible options are listed at https://jasmine.github.io/api/edge/Configuration.html
+        // for example, you can disable the random execution with `random: false`
+        // or set a specific seed with `seed: 4321`
+      },
+      clearContext: false // leave Jasmine Spec Runner output visible in browser
+    },
+    jasmineHtmlReporter: {
+      suppressAll: true // removes the duplicated traces
+    },
+    coverageReporter: {
+      dir: require('path').join(__dirname, '<%= relativePathToWorkspaceRoot %>/coverage/<%= folderName %>'),
+      subdir: '.',
+      reporters: [
+        { type: 'html' },
+        { type: 'text-summary' }
+      ]
+    },
+    reporters: ['progress', 'kjhtml'],
+    browsers: ['Chrome'],
+    restartOnFileChange: true
+  });
+};

packages/schematics/angular/config/index.ts

@@ -0,0 +1,95 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {
+  Rule,
+  SchematicsException,
+  apply,
+  applyTemplates,
+  filter,
+  mergeWith,
+  move,
+  strings,
+  url,
+} from '@angular-devkit/schematics';
+import { AngularBuilder, readWorkspace, updateWorkspace } from '@schematics/angular/utility';
+import { posix as path } from 'path';
+import { relativePathToWorkspaceRoot } from '../utility/paths';
+import { Schema as ConfigOptions, Type as ConfigType } from './schema';
+
+export default function (options: ConfigOptions): Rule {
+  switch (options.type) {
+    case ConfigType.Karma:
+      return addKarmaConfig(options);
+    case ConfigType.Browserslist:
+      return addBrowserslistConfig(options);
+    default:
+      throw new SchematicsException(`"${options.type}" is an unknown configuration file type.`);
+  }
+}
+
+function addBrowserslistConfig(options: ConfigOptions): Rule {
+  return async (host) => {
+    const workspace = await readWorkspace(host);
+    const project = workspace.projects.get(options.project);
+    if (!project) {
+      throw new SchematicsException(`Project name "${options.project}" doesn't not exist.`);
+    }
+
+    return mergeWith(
+      apply(url('./files'), [
+        filter((p) => p.endsWith('.browserslistrc.template')),
+        applyTemplates({}),
+        move(project.root),
+      ]),
+    );
+  };
+}
+
+function addKarmaConfig(options: ConfigOptions): Rule {
+  return updateWorkspace((workspace) => {
+    const project = workspace.projects.get(options.project);
+    if (!project) {
+      throw new SchematicsException(`Project name "${options.project}" doesn't not exist.`);
+    }
+
+    const testTarget = project.targets.get('test');
+    if (!testTarget) {
+      throw new SchematicsException(
+        `No "test" target found for project "${options.project}".` +
+          ' A "test" target is required to generate a karma configuration.',
+      );
+    }
+
+    if (testTarget.builder !== AngularBuilder.Karma) {
+      throw new SchematicsException(
+        `Cannot add a karma configuration as builder for "test" target in project does not use "${AngularBuilder.Karma}".`,
+      );
+    }
+
+    testTarget.options ??= {};
+    testTarget.options.karmaConfig = path.join(project.root, 'karma.conf.js');
+
+    // If scoped project (i.e. "@foo/bar"), convert dir to "foo/bar".
+    let folderName = options.project.startsWith('@') ? options.project.slice(1) : options.project;
+    if (/[A-Z]/.test(folderName)) {
+      folderName = strings.dasherize(folderName);
+    }
+
+    return mergeWith(
+      apply(url('./files'), [
+        filter((p) => p.endsWith('karma.conf.js.template')),
+        applyTemplates({
+          relativePathToWorkspaceRoot: relativePathToWorkspaceRoot(project.root),
+          folderName,
+        }),
+        move(project.root),
+      ]),
+    );
+  });
+}

packages/schematics/angular/config/index_spec.ts

@@ -0,0 +1,82 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import { SchematicTestRunner, UnitTestTree } from '@angular-devkit/schematics/testing';
+import { Schema as ApplicationOptions } from '../application/schema';
+import { Schema as WorkspaceOptions } from '../workspace/schema';
+import { Schema as ConfigOptions, Type as ConfigType } from './schema';
+
+describe('Application Schematic', () => {
+  const schematicRunner = new SchematicTestRunner(
+    '@schematics/angular',
+    require.resolve('../collection.json'),
+  );
+
+  const workspaceOptions: WorkspaceOptions = {
+    name: 'workspace',
+    newProjectRoot: 'projects',
+    version: '15.0.0',
+  };
+
+  const defaultAppOptions: ApplicationOptions = {
+    name: 'foo',
+    inlineStyle: true,
+    inlineTemplate: true,
+    routing: false,
+    skipPackageJson: false,
+  };
+
+  let applicationTree: UnitTestTree;
+  function runConfigSchematic(type: ConfigType): Promise<UnitTestTree> {
+    return schematicRunner.runSchematic<ConfigOptions>(
+      'config',
+      {
+        project: 'foo',
+        type,
+      },
+      applicationTree,
+    );
+  }
+
+  beforeEach(async () => {
+    const workspaceTree = await schematicRunner.runSchematic('workspace', workspaceOptions);
+    applicationTree = await schematicRunner.runSchematic(
+      'application',
+      defaultAppOptions,
+      workspaceTree,
+    );
+  });
+
+  describe(`when 'type' is 'karma'`, () => {
+    it('should create a karma.conf.js file', async () => {
+      const tree = await runConfigSchematic(ConfigType.Karma);
+      expect(tree.exists('projects/foo/karma.conf.js')).toBeTrue();
+    });
+
+    it('should set the right coverage folder', async () => {
+      const tree = await runConfigSchematic(ConfigType.Karma);
+      const karmaConf = tree.readText('projects/foo/karma.conf.js');
+      expect(karmaConf).toContain(`dir: require('path').join(__dirname, '../../coverage/foo')`);
+    });
+
+    it(`should set 'karmaConfig' in test builder`, async () => {
+      const tree = await runConfigSchematic(ConfigType.Karma);
+      const config = JSON.parse(tree.readContent('/angular.json'));
+      const prj = config.projects.foo;
+      const { karmaConfig } = prj.architect.test.options;
+      expect(karmaConfig).toBe('projects/foo/karma.conf.js');
+    });
+  });
+
+  describe(`when 'type' is 'browserslist'`, () => {
+    it('should create a .browserslistrc file', async () => {
+      const tree = await runConfigSchematic(ConfigType.Browserslist);
+      expect(tree.exists('projects/foo/.browserslistrc')).toBeTrue();
+    });
+  });
+});

packages/schematics/angular/config/schema.json

@@ -0,0 +1,28 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema",
+  "$id": "SchematicsAngularConfig",
+  "title": "Angular Config File Options Schema",
+  "type": "object",
+  "additionalProperties": false,
+  "description": "Generates a configuration file in the given project.",
+  "properties": {
+    "project": {
+      "type": "string",
+      "description": "The name of the project.",
+      "$default": {
+        "$source": "projectName"
+      }
+    },
+    "type": {
+      "type": "string",
+      "description": "Specifies which type of configuration file to create.",
+      "enum": ["karma", "browserslist"],
+      "x-prompt": "Which type of configuration file would you like to create?",
+      "$default": {
+        "$source": "argv",
+        "index": 0
+      }
+    }
+  },
+  "required": ["project", "type"]
+}

tests/legacy-cli/e2e/tests/generate/confg/type-browserslist.ts

@@ -0,0 +1,6 @@
+import { ng } from '../../../utils/process';
+
+export default async function () {
+  await ng('generate', 'config', 'browserslist');
+  await ng('build');
+}

tests/legacy-cli/e2e/tests/generate/confg/type-karma.ts

@@ -0,0 +1,6 @@
+import { ng } from '../../../utils/process';
+
+export default async function () {
+  await ng('generate', 'config', 'karma');
+  await ng('test', '--watch=false');
+}