feat: 🎸 add --clean flag to Storybook CLI

src/dev/storybook/commands/clean.ts

@@ -0,0 +1,31 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { ToolingLog } from '@kbn/dev-utils';
+import { join } from 'path';
+import del from 'del';
+
+export const clean = async ({ log, rootDir }: { log: ToolingLog; rootDir: string }) => {
+  log.info('Cleaning Storybook build folder');
+
+  const dir = join(rootDir, 'built_assets', 'storybook');
+  log.info('Deleting folder:', dir);
+  await del([join(dir, '*')]);
+  await del([dir]);
+};

src/dev/storybook/run_storybook_cli.ts

@@ -20,6 +20,7 @@
 import { join } from 'path';
 import { run, createFlagError } from '@kbn/dev-utils';
 import { storybookAliases } from './aliases';
+import { clean } from './commands/clean';
 
 const rootDir = join(__dirname, '..', '..', '..');
 
@@ -30,6 +31,15 @@ run(
       _: [alias],
     } = flags;
 
+    if (flags.verbose) {
+      log.info('Flags:', flags);
+    }
+
+    if (flags.clean) {
+      await clean({ log, rootDir });
+      return;
+    }
+
     if (!alias) {
       throw createFlagError('missing alias');
     }
@@ -58,10 +68,12 @@ run(
       Add your alias in src/dev/storybook/aliases.ts
     `,
     flags: {
-      boolean: ['fix'],
-      default: {
-        fix: false,
-      },
+      default: {},
+      string: [],
+      boolean: ['clean'],
+      help: `
+      --clean            Clean Storybook build folder.
+    `,
     },
   }
 );