feat: Add Storybook for component documentation, testing, and development (#34907)

Co-authored-by: Echo <ChaosExAnima@users.noreply.github.com>
Co-authored-by: Renaud Chaput <renchap@gmail.com>

.github/workflows/chromatic.yml

@@ -0,0 +1,40 @@
+name: 'Chromatic'
+
+on:
+  push:
+    branches-ignore:
+      - renovate/*
+      - stable-*
+    paths:
+      - 'package.json'
+      - 'yarn.lock'
+      - '**/*.js'
+      - '**/*.jsx'
+      - '**/*.ts'
+      - '**/*.tsx'
+      - '**/*.css'
+      - '**/*.scss'
+      - '.github/workflows/chromatic.yml'
+
+jobs:
+  chromatic:
+    name: Run Chromatic
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Set up Javascript environment
+        uses: ./.github/actions/setup-javascript
+
+      - name: Build Storybook
+        run: yarn build-storybook
+
+      - name: Run Chromatic
+        uses: chromaui/action@v12
+        with:
+          # ⚠️ Make sure to configure a `CHROMATIC_PROJECT_TOKEN` repository secret
+          projectToken: ${{ secrets.CHROMATIC_PROJECT_TOKEN }}
+          zip: true
+          storybookBuildDir: 'storybook-static'

.gitignore

@@ -75,3 +75,6 @@ docker-compose.override.yml
 
 # Ignore local-only rspec configuration
 .rspec-local
+
+*storybook.log
+storybook-static

.storybook/main.ts

@@ -0,0 +1,16 @@
+import type { StorybookConfig } from '@storybook/react-vite';
+
+const config: StorybookConfig = {
+  stories: ['../app/javascript/**/*.stories.@(js|jsx|mjs|ts|tsx)'],
+  addons: [
+    '@storybook/addon-docs',
+    '@storybook/addon-a11y',
+    '@storybook/addon-vitest',
+  ],
+  framework: {
+    name: '@storybook/react-vite',
+    options: {},
+  },
+};
+
+export default config;

.storybook/manager.ts

@@ -0,0 +1,7 @@
+import { addons } from 'storybook/manager-api';
+
+import theme from './storybook-theme';
+
+addons.setConfig({
+  theme,
+});

.storybook/preview-head.html

@@ -0,0 +1,18 @@
+<style>
+	/* Increase docs font size */
+	.sbdocs.sbdocs-content :where(p:not(.sb-anchor, .sb-unstyled, .sb-unstyled p)),
+	.sbdocs.sbdocs-content :where(li:not(.sb-anchor, .sb-unstyled, .sb-unstyled li)) {
+		font-size: 1.0666rem; /* 17px */
+		line-height: 1.585; /* 27px */
+	}
+
+	.sbdocs.sbdocs-content :where(p:not(.sb-anchor, .sb-unstyled, .sb-unstyled p)) code,
+	.sbdocs.sbdocs-content :where(li:not(.sb-anchor, .sb-unstyled, .sb-unstyled li)) code {
+		font-size: 0.875rem; /* ~15px */
+	}
+
+	/* Bring numbers back for ordered lists */
+	ol {
+		list-style: revert !important;
+	}
+</style>

.storybook/preview.ts

@@ -0,0 +1,29 @@
+import type { Preview } from '@storybook/react-vite';
+
+// If you want to run the dark theme during development,
+// you can change the below to `/application.scss`
+import '../app/javascript/styles/mastodon-light.scss';
+
+const preview: Preview = {
+  // Auto-generate docs: https://storybook.js.org/docs/writing-docs/autodocs
+  tags: ['autodocs'],
+  parameters: {
+    layout: 'centered',
+
+    controls: {
+      matchers: {
+        color: /(background|color)$/i,
+        date: /Date$/i,
+      },
+    },
+
+    a11y: {
+      // 'todo' - show a11y violations in the test UI only
+      // 'error' - fail CI on a11y violations
+      // 'off' - skip a11y checks entirely
+      test: 'todo',
+    },
+  },
+};
+
+export default preview;

.storybook/storybook-addon-vitest.d.ts

@@ -0,0 +1,7 @@
+// The addon package.json incorrectly exports types, so we need to override them here.
+// See: https://github.com/storybookjs/storybook/blob/v9.0.4/code/addons/vitest/package.json#L70-L76
+declare module '@storybook/addon-vitest/vitest-plugin' {
+  export * from '@storybook/addon-vitest/dist/vitest-plugin/index';
+}
+
+export {};

.storybook/storybook-theme.ts

@@ -0,0 +1,7 @@
+import { create } from 'storybook/theming';
+
+export default create({
+  base: 'light',
+  brandTitle: 'Mastodon Storybook',
+  brandImage: 'https://joinmastodon.org/logos/wordmark-black-text.svg',
+});

.storybook/vitest.setup.ts

@@ -0,0 +1,8 @@
+import * as a11yAddonAnnotations from '@storybook/addon-a11y/preview';
+import { setProjectAnnotations } from '@storybook/react-vite';
+
+import * as projectAnnotations from './preview';
+
+// This is an important step to apply the right configuration when testing your stories.
+// More info at: https://storybook.js.org/docs/api/portable-stories/portable-stories-vitest#setprojectannotations
+setProjectAnnotations([a11yAddonAnnotations, projectAnnotations]);

app/javascript/mastodon/components/button/button.stories.tsx

@@ -0,0 +1,97 @@
+import type { Meta, StoryObj } from '@storybook/react-vite';
+import { fn, expect } from 'storybook/test';
+
+import { Button } from '.';
+
+const meta = {
+  title: 'Components/Button',
+  component: Button,
+  args: {
+    secondary: false,
+    compact: false,
+    dangerous: false,
+    disabled: false,
+    onClick: fn(),
+  },
+  argTypes: {
+    text: {
+      control: 'text',
+      type: 'string',
+      description:
+        'Alternative way of specifying the button label. Will override `children` if provided.',
+    },
+    type: {
+      type: 'string',
+      control: 'text',
+      table: {
+        type: { summary: 'string' },
+      },
+    },
+  },
+  tags: ['test'],
+} satisfies Meta<typeof Button>;
+
+export default meta;
+
+type Story = StoryObj<typeof meta>;
+
+const buttonTest: Story['play'] = async ({ args, canvas, userEvent }) => {
+  await userEvent.click(canvas.getByRole('button'));
+  await expect(args.onClick).toHaveBeenCalled();
+};
+
+const disabledButtonTest: Story['play'] = async ({
+  args,
+  canvas,
+  userEvent,
+}) => {
+  await userEvent.click(canvas.getByRole('button'));
+  await expect(args.onClick).not.toHaveBeenCalled();
+};
+
+export const Primary: Story = {
+  args: {
+    children: 'Primary button',
+  },
+  play: buttonTest,
+};
+
+export const Secondary: Story = {
+  args: {
+    secondary: true,
+    children: 'Secondary button',
+  },
+  play: buttonTest,
+};
+
+export const Compact: Story = {
+  args: {
+    compact: true,
+    children: 'Compact button',
+  },
+  play: buttonTest,
+};
+
+export const Dangerous: Story = {
+  args: {
+    dangerous: true,
+    children: 'Dangerous button',
+  },
+  play: buttonTest,
+};
+
+export const PrimaryDisabled: Story = {
+  args: {
+    ...Primary.args,
+    disabled: true,
+  },
+  play: disabledButtonTest,
+};
+
+export const SecondaryDisabled: Story = {
+  args: {
+    ...Secondary.args,
+    disabled: true,
+  },
+  play: disabledButtonTest,
+};

app/javascript/mastodon/components/button/index.tsx

@@ -22,6 +22,10 @@ interface PropsWithText extends BaseProps {
 
 type Props = PropsWithText | PropsChildren;
 
+/**
+ * Primary UI component for user interaction that doesn't result in navigation.
+ */
+
 export const Button: React.FC<Props> = ({
   type = 'button',
   onClick,

eslint.config.mjs

@@ -12,6 +12,7 @@ import jsxA11Y from 'eslint-plugin-jsx-a11y';
 import promisePlugin from 'eslint-plugin-promise';
 import react from 'eslint-plugin-react';
 import reactHooks from 'eslint-plugin-react-hooks';
+import storybook from 'eslint-plugin-storybook';
 import globals from 'globals';
 import tseslint from 'typescript-eslint';
 
@@ -187,6 +188,7 @@ export default tseslint.config([
   importPlugin.flatConfigs.react,
   // @ts-expect-error -- For some reason the formatjs package exports an empty object?
   formatjs.configs.strict,
+  storybook.configs['flat/recommended'],
   {
     languageOptions: {
       globals: {
@@ -252,6 +254,11 @@ export default tseslint.config([
             'app/javascript/mastodon/test_setup.js',
             'app/javascript/mastodon/test_helpers.tsx',
             'app/javascript/**/__tests__/**',
+            'app/javascript/**/*.stories.ts',
+            'app/javascript/**/*.stories.tsx',
+            'app/javascript/**/*.test.ts',
+            'app/javascript/**/*.test.tsx',
+            '.storybook/**/*.ts',
           ],
         },
       ],
@@ -398,4 +405,18 @@ export default tseslint.config([
       globals: globals.vitest,
     },
   },
+  {
+    files: ['**/*.stories.ts', '**/*.stories.tsx', '.storybook/**/*.ts'],
+    rules: {
+      'import/no-default-export': 'off',
+    },
+  },
+  {
+    files: ['vitest.shims.d.ts'],
+    rules: {
+      '@typescript-eslint/no-unnecessary-boolean-literal-compare': 'off',
+      '@typescript-eslint/no-unnecessary-condition': 'off',
+      '@typescript-eslint/prefer-nullish-coalescing': 'off',
+    },
+  },
 ]);

package.json

@@ -26,8 +26,12 @@
     "postinstall": "test -d node_modules/husky && husky || echo \"husky is not installed\"",
     "start": "node ./streaming/index.js",
     "test": "yarn lint && yarn run typecheck && yarn test:js run",
-    "test:js": "vitest",
-    "typecheck": "tsc --noEmit"
+    "test:js": "vitest --project=legacy-tests",
+    "test:storybook": "vitest --project=storybook",
+    "typecheck": "tsc --noEmit",
+    "storybook": "storybook dev -p 6006",
+    "build-storybook": "VITE_RUBY_PUBLIC_OUTPUT_DIR='.' VITE_RUBY_PUBLIC_DIR='./storybook-static' storybook build",
+    "chromatic": "npx chromatic -d storybook-static"
   },
   "repository": {
     "type": "git",
@@ -122,6 +126,10 @@
   "devDependencies": {
     "@eslint/js": "^9.23.0",
     "@formatjs/cli": "^6.1.1",
+    "@storybook/addon-a11y": "^9.0.4",
+    "@storybook/addon-docs": "^9.0.4",
+    "@storybook/addon-vitest": "^9.0.4",
+    "@storybook/react-vite": "^9.0.4",
     "@testing-library/dom": "^10.2.0",
     "@testing-library/react": "^16.0.0",
     "@types/emoji-mart": "3.0.14",
@@ -147,6 +155,10 @@
     "@types/react-toggle": "^4.0.3",
     "@types/redux-immutable": "^4.0.3",
     "@types/requestidlecallback": "^0.3.5",
+    "@vitest/browser": "^3.2.1",
+    "@vitest/coverage-v8": "^3.2.0",
+    "@vitest/ui": "^3.2.1",
+    "chromatic": "^12.1.0",
     "eslint": "^9.23.0",
     "eslint-import-resolver-typescript": "^4.2.5",
     "eslint-plugin-formatjs": "^5.3.1",
@@ -156,11 +168,14 @@
     "eslint-plugin-promise": "~7.2.1",
     "eslint-plugin-react": "^7.37.4",
     "eslint-plugin-react-hooks": "^5.2.0",
+    "eslint-plugin-storybook": "^9.0.4",
     "globals": "^16.0.0",
     "husky": "^9.0.11",
     "lint-staged": "^16.0.0",
+    "playwright": "^1.52.0",
     "prettier": "^3.3.3",
     "react-test-renderer": "^18.2.0",
+    "storybook": "^9.0.4",
     "stylelint": "^16.19.1",
     "stylelint-config-prettier-scss": "^1.0.0",
     "stylelint-config-standard-scss": "^15.0.1",
@@ -168,13 +183,14 @@
     "typescript-eslint": "^8.29.1",
     "vite-plugin-rails": "^0.5.0",
     "vite-plugin-svgr": "^4.2.0",
-    "vitest": "^3.1.3"
+    "vitest": "^3.2.1"
   },
   "resolutions": {
     "@types/react": "^18.2.7",
     "@types/react-dom": "^18.2.4",
     "kind-of": "^6.0.3",
-    "vite-plugin-ruby": "^5.1.0"
+    "vite-plugin-ruby": "^5.1.0",
+    "vite": "^6.3.5"
   },
   "peerDependenciesMeta": {
     "react": {

tsconfig.json

@@ -27,9 +27,12 @@
   },
   "include": [
     "vite.config.mts",
+    "vitest.config.mts",
     "config/vite",
     "app/javascript/mastodon",
     "app/javascript/entrypoints",
-    "app/javascript/types"
+    "app/javascript/types",
+    ".storybook/*.ts",
+    ".storybook/*.tsx"
   ]
 }

vitest.config.mts

@@ -1,26 +1,69 @@
-import { configDefaults, defineConfig } from 'vitest/config';
+import { resolve } from 'node:path';
+
+import { storybookTest } from '@storybook/addon-vitest/vitest-plugin';
+import react from '@vitejs/plugin-react';
+import svgr from 'vite-plugin-svgr';
+import tsconfigPaths from 'vite-tsconfig-paths';
+import {
+  configDefaults,
+  defineConfig,
+  TestProjectInlineConfiguration,
+} from 'vitest/config';
 
 import { config as viteConfig } from './vite.config.mjs';
 
+const storybookTests: TestProjectInlineConfiguration = {
+  plugins: [
+    // See options at: https://storybook.js.org/docs/next/writing-tests/integrations/vitest-addon#storybooktest
+    storybookTest({
+      configDir: '.storybook',
+      storybookScript: 'yarn run storybook',
+    }),
+    react(),
+    svgr(),
+    tsconfigPaths(),
+  ],
+  test: {
+    name: 'storybook',
+    browser: {
+      enabled: true,
+      headless: true,
+      provider: 'playwright',
+      instances: [{ browser: 'chromium' }],
+    },
+    setupFiles: [resolve(__dirname, '.storybook/vitest.setup.ts')],
+  },
+};
+
+const legacyTests: TestProjectInlineConfiguration = {
+  extends: true,
+  test: {
+    name: 'legacy-tests',
+    environment: 'jsdom',
+    include: [
+      ...configDefaults.include,
+      '**/__tests__/**/*.{js,mjs,cjs,ts,mts,cts,jsx,tsx}',
+    ],
+    exclude: [
+      ...configDefaults.exclude,
+      '**/node_modules/**',
+      'vendor/**',
+      'config/**',
+      'log/**',
+      'public/**',
+      'tmp/**',
+    ],
+    globals: true,
+  },
+};
+
 export default defineConfig(async (context) => {
+  const baseConfig = await viteConfig(context);
+
   return {
-    ...(await viteConfig(context)),
+    ...baseConfig,
     test: {
-      environment: 'jsdom',
-      include: [
-        ...configDefaults.include,
-        '**/__tests__/**/*.{js,mjs,cjs,ts,mts,cts,jsx,tsx}',
-      ],
-      exclude: [
-        ...configDefaults.exclude,
-        '**/node_modules/**',
-        'vendor/**',
-        'config/**',
-        'log/**',
-        'public/**',
-        'tmp/**',
-      ],
-      globals: true,
+      projects: [legacyTests, storybookTests],
     },
   };
 });

vitest.shims.d.ts

@@ -0,0 +1 @@
+/// <reference types="@vitest/browser/providers/playwright" />