Addon: Create @storybook/addon-themes

code/addons/essentials/package.json

@@ -93,6 +93,16 @@
       "require": "./dist/outline/manager.js",
       "import": "./dist/outline/manager.mjs"
     },
+    "./themes/manager": {
+      "types": "./dist/themes/manager.d.ts",
+      "require": "./dist/themes/manager.js",
+      "import": "./dist/themes/manager.mjs"
+    },
+    "./themes/preview": {
+      "types": "./dist/themes/preview.d.ts",
+      "require": "./dist/themes/preview.js",
+      "import": "./dist/themes/preview.mjs"
+    },
     "./toolbars/manager": {
       "types": "./dist/toolbars/manager.d.ts",
       "require": "./dist/toolbars/manager.js",
@@ -126,6 +136,7 @@
     "@storybook/addon-highlight": "7.2.0-alpha.0",
     "@storybook/addon-measure": "7.2.0-alpha.0",
     "@storybook/addon-outline": "7.2.0-alpha.0",
+    "@storybook/addon-themes": "7.2.0-alpha.0",
     "@storybook/addon-toolbars": "7.2.0-alpha.0",
     "@storybook/addon-viewport": "7.2.0-alpha.0",
     "@storybook/core-common": "7.2.0-alpha.0",
@@ -162,7 +173,9 @@
       "./src/outline/preview.ts",
       "./src/outline/manager.ts",
       "./src/toolbars/manager.ts",
-      "./src/viewport/manager.ts"
+      "./src/viewport/manager.ts",
+      "./src/themes/manager.ts",
+      "./src/themes/preview.ts"
     ],
     "platform": "node"
   },

code/addons/essentials/src/index.ts

@@ -3,15 +3,16 @@ import { logger } from '@storybook/node-logger';
 import { serverRequire } from '@storybook/core-common';
 
 interface PresetOptions {
-  configDir: string;
-  docs?: boolean;
-  controls?: boolean;
   actions?: boolean;
   backgrounds?: boolean;
-  viewport?: boolean;
-  toolbars?: boolean;
+  configDir: string;
+  controls?: boolean;
+  docs?: boolean;
   measure?: boolean;
   outline?: boolean;
+  themes?: boolean;
+  toolbars?: boolean;
+  viewport?: boolean;
 }
 
 const requireMain = (configDir: string) => {
@@ -37,6 +38,8 @@ export function addons(options: PresetOptions) {
   };
 
   const main = requireMain(options.configDir);
+
+  // NOTE: The order of these addons is important.
   return [
     'docs',
     'controls',
@@ -47,6 +50,7 @@ export function addons(options: PresetOptions) {
     'measure',
     'outline',
     'highlight',
+    'themes',
   ]
     .filter((key) => (options as any)[key] !== false)
     .filter((addon) => !checkInstalled(addon, main))

code/addons/essentials/src/themes/manager.ts

@@ -0,0 +1 @@
+export * from '@storybook/addon-themes/manager';

code/addons/essentials/src/themes/preview.ts

@@ -0,0 +1,2 @@
+// eslint-disable-next-line import/export
+export * from '@storybook/addon-themes/preview';

code/addons/themes/README.md

@@ -0,0 +1,72 @@
+# `@storybook/addon-themes
+
+Storybook Addon Themes can be used which between multiple themes for components inside the preview in [Storybook](https://storybook.js.org).
+
+![React Storybook Screenshot](https://user-images.githubusercontent.com/42671/98158421-dada2300-1ea8-11eb-8619-af1e7018e1ec.png)
+
+## Usage
+
+Requires Storybook 7.0 or later. Themes is part of [essentials](https://storybook.js.org/docs/react/essentials/introduction) and so is installed in all new Storybooks by default. If you need to add it to your Storybook, you can run:
+
+```sh
+npm i -D @storybook/addon-themes
+```
+
+Then, add following content to [`.storybook/main.js`](https://storybook.js.org/docs/react/configure/overview#configure-your-storybook-project):
+
+```js
+export default {
+  addons: ['@storybook/addon-themes'],
+};
+```
+
+### 👇 Tool specific configuration
+
+For tool-specific setup, check out the recipes below
+
+- [`@emotion/styled`](https://github.com/storybookjs/storybook/tree/next/code/addons/themes/docs/getting-started/emotion.md)
+- [`@mui/material`](https://github.com/storybookjs/storybook/tree/next/code/addons/themes/docs/getting-started/material-ui.md)
+- [`bootstrap`](https://github.com/storybookjs/storybook/tree/next/code/addons/themes/docs/getting-started/bootstrap.md)
+- [`styled-components`](https://github.com/storybookjs/storybook/tree/next/code/addons/themes/docs/getting-started/styled-components.md)
+- [`tailwind`](https://github.com/storybookjs/storybook/tree/next/code/addons/themes/docs/getting-started/tailwind.md)
+- [`[email protected]`](https://github.com/storybookjs/storybook/blob/next/code/addons/themes/docs/api.md#writing-a-custom-decorator)
+
+Don't see your favorite tool listed? Don't worry! That doesn't mean this addon isn't for you. Check out the ["Writing a custom decorator"](https://github.com/storybookjs/storybook/blob/next/code/addons/themes/docs/api.md#writing-a-custom-decorator) section of the [api reference](https://github.com/storybookjs/storybook/blob/next/code/addons/themes/docs/api.md).
+
+### ❗️ Overriding theme
+
+If you want to override your theme for a particular component or story, you can use the `themes.themeOverride` parameter.
+
+```js
+import React from 'react';
+import { Button } from './Button';
+
+export default {
+  title: 'Example/Button',
+  component: Button,
+  parameters: {
+    themes: {
+      themeOverride: 'light', // component level override
+    },
+  },
+};
+
+export const Primary = {
+  args: {
+    primary: true,
+    label: 'Button',
+  },
+};
+
+export const PrimaryDark = {
+  args: {
+    primary: true,
+    label: 'Button',
+  },
+  parameters: {
+    themes: {
+      themeOverride: 'dark', // Story level override
+    },
+  },
+};
+```

code/addons/themes/docs/api.md

@@ -0,0 +1,206 @@
+# API
+
+## Decorators
+
+### `withThemeFromJSXProvider`
+
+Takes your provider component, global styles, and theme(s)to wrap your stories in.
+
+```js
+import { withThemeFromJSXProvider } from '@storybook/addon-styling';
+
+export const decorators = [
+  withThemeFromJSXProvider({
+    themes: {
+      light: lightTheme,
+      dark: darkTheme,
+    },
+    defaultTheme: 'light',
+    Provider: ThemeProvider,
+    GlobalStyles: CssBaseline,
+  }),
+];
+```
+
+Available options:
+
+| option       | type                  | required? | Description                                                                                                                                                                                         |
+| ------------ | --------------------- | :-------: | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| themes       | `Record<string, any>` |           | An object of theme configurations where the key is the name of the theme and the value is the theme object. If multiple themes are provided, a toolbar item will be added to switch between themes. |
+| defaultTheme | `string`              |           | The name of the default theme to use                                                                                                                                                                |
+| Provider     |                       |           | The JSX component to provide themes                                                                                                                                                                 |
+| GlobalStyles |                       |           | A JSX component containing global css styles.                                                                                                                                                       |
+
+### `withThemeByClassName`
+
+Takes your theme class names to apply your parent element to enable your theme(s).
+
+```js
+import { withThemeByClassName } from '@storybook/addon-styling';
+
+export const decorators = [
+  withThemeByClassName({
+    themes: {
+      light: 'light-theme',
+      dark: 'dark-theme',
+    },
+    defaultTheme: 'light',
+  }),
+];
+```
+
+Available options:
+
+| option         | type                     | required? | Description                                                                                                     |
+| -------------- | ------------------------ | :-------: | --------------------------------------------------------------------------------------------------------------- |
+| themes         | `Record<string, string>` |    ✅     | An object of theme configurations where the key is the name of the theme and the value is the theme class name. |
+| defaultTheme   | `string`                 |    ✅     | The name of the default theme to use                                                                            |
+| parentSelector | `string`                 |           | The selector for the parent element that you want to apply your theme class to. Defaults to "html"              |
+
+### `withThemeByDataAttribute`
+
+Takes your theme names and data attribute to apply your parent element to enable your theme(s).
+
+```js
+import { withThemeByDataAttribute } from '@storybook/addon-styling';
+
+export const decorators = [
+  withThemeByDataAttribute({
+    themes: {
+      light: 'light',
+      dark: 'dark',
+    },
+    defaultTheme: 'light',
+    attributeName: 'data-bs-theme',
+  }),
+];
+```
+
+available options:
+
+| option         | type                     | required? | Description                                                                                                         |
+| -------------- | ------------------------ | :-------: | ------------------------------------------------------------------------------------------------------------------- |
+| themes         | `Record<string, string>` |    ✅     | An object of theme configurations where the key is the name of the theme and the value is the data attribute value. |
+| defaultTheme   | `string`                 |    ✅     | The name of the default theme to use                                                                                |
+| parentSelector | `string`                 |           | The selector for the parent element that you want to apply your theme class to. Defaults to "html"                  |
+| attributeName  | `string`                 |           | The name of the data attribute to set on the parent element for your theme(s). Defaults to "data-theme"             |
+
+## Writing a custom decorator
+
+If none of these decorators work for your library there is still hope. We've provided a collection of helper functions to get access to the theme toggling state so that you can create a decorator of your own.
+
+### `pluckThemeFromContext`
+
+Pulls the selected theme from storybook's global state.
+
+```js
+import { DecoratorHelpers } from '@storybook/addon-styling';
+const { pluckThemeFromContext } = DecoratorHelpers;
+
+export const myCustomDecorator =
+  ({ themes, defaultState, ...rest }) =>
+  (storyFn, context) => {
+    const selectedTheme = pluckThemeFromContext(context);
+
+    // Snipped
+  };
+```
+
+### `useThemeParameters`
+
+Returns the theme parameters for this addon.
+
+```js
+import { DecoratorHelpers } from '@storybook/addon-styling';
+const { useThemeParameters } = DecoratorHelpers;
+
+export const myCustomDecorator =
+  ({ themes, defaultState, ...rest }) =>
+  (storyFn, context) => {
+    const { themeOverride } = useThemeParameters();
+
+    // Snipped
+  };
+```
+
+### `initializeThemeState`
+
+Used to register the themes and defaultTheme with the addon state.
+
+```js
+import { DecoratorHelpers } from '@storybook/addon-styling';
+const { initializeThemeState } = DecoratorHelpers;
+
+export const myCustomDecorator = ({ themes, defaultState, ...rest }) => {
+  initializeThemeState(Object.keys(themes), defaultTheme);
+
+  return (storyFn, context) => {
+    // Snipped
+  };
+};
+```
+
+### Putting it all together
+
+Let's use Vuetify as an example. Vuetify uses it's own global state to know which theme to render. To build a custom decorator to accommodate this method we'll need to do the following
+
+```js
+// .storybook/withVeutifyTheme.decorator.js
+
+import { DecoratorHelpers } from '@storybook/addon-styling';
+import { useTheme } from 'vuetify';
+
+const { initializeThemeState, pluckThemeFromContext, useThemeParameters } = DecoratorHelpers;
+
+export const withVuetifyTheme = ({ themes, defaultTheme }) => {
+  initializeThemeState(Object.keys(themes), defaultTheme);
+
+  return (story, context) => {
+    const selectedTheme = pluckThemeFromContext(context);
+    const { themeOverride } = useThemeParameters();
+
+    const selected = themeOverride || selectedTheme || defaultTheme;
+
+    return {
+      components: { story },
+      setup() {
+        const theme = useTheme();
+
+        theme.global.name.value = selected;
+
+        return {
+          theme,
+        };
+      },
+      template: `<v-app><story /></v-app>`,
+    };
+  };
+};
+```
+
+This can then be provided to Storybook in `.storybook/preview.js`:
+
+```js
+// .storybook/preview.js
+
+import { setup } from '@storybook/vue3';
+import { registerPlugins } from '../src/plugins';
+import { withVuetifyTheme } from './withVuetifyTheme.decorator';
+
+setup((app) => {
+  registerPlugins(app);
+});
+
+/* snipped for brevity */
+
+export const decorators = [
+  withVuetifyTheme({
+    themes: {
+      light: 'light',
+      dark: 'dark',
+      customTheme: 'myCustomTheme',
+    },
+    defaultTheme: 'customTheme', // The key of your default theme
+  }),
+];
+```