feat(core): site storage config options (experimental)

packages/docusaurus-module-type-aliases/src/index.d.ts

@@ -26,6 +26,13 @@ declare module '@generated/site-metadata' {
   export = siteMetadata;
 }
 
+declare module '@generated/site-storage' {
+  import type {SiteStorage} from '@docusaurus/types';
+
+  const siteStorage: SiteStorage;
+  export = siteStorage;
+}
+
 declare module '@generated/registry' {
   import type {Registry} from '@docusaurus/types';
 

packages/docusaurus-theme-classic/src/index.ts

@@ -10,7 +10,7 @@ import {createRequire} from 'module';
 import rtlcss from 'rtlcss';
 import {readDefaultCodeTranslationMessages} from '@docusaurus/theme-translations';
 import {getTranslationFiles, translateThemeConfig} from './translations';
-import type {LoadContext, Plugin} from '@docusaurus/types';
+import type {LoadContext, Plugin, SiteStorage} from '@docusaurus/types';
 import type {ThemeConfig} from '@docusaurus/theme-common';
 import type {Plugin as PostCssPlugin} from 'postcss';
 import type {PluginOptions} from '@docusaurus/theme-classic';
@@ -23,58 +23,66 @@ const ContextReplacementPlugin = requireFromDocusaurusCore(
   'webpack/lib/ContextReplacementPlugin',
 ) as typeof webpack.ContextReplacementPlugin;
 
-// Need to be inlined to prevent dark mode FOUC
-// Make sure the key is the same as the one in `/theme/hooks/useTheme.js`
-const ThemeStorageKey = 'theme';
 // Support for ?docusaurus-theme=dark
 const ThemeQueryStringKey = 'docusaurus-theme';
 // Support for ?docusaurus-data-mode=embed&docusaurus-data-myAttr=42
 const DataQueryStringPrefixKey = 'docusaurus-data-';
 
 const noFlashColorMode = ({
-  defaultMode,
-  respectPrefersColorScheme,
-}: ThemeConfig['colorMode']) =>
+  colorMode: {defaultMode, respectPrefersColorScheme},
+  siteStorage,
+}: {
+  colorMode: ThemeConfig['colorMode'];
+  siteStorage: SiteStorage;
+}) => {
+  // Need to be inlined to prevent dark mode FOUC
+  // Make sure the key is the same as the one in the color mode React context
+  // Currently defined in: `docusaurus-theme-common/src/contexts/colorMode.tsx`
+  const themeStorageKey = `theme${siteStorage.namespace}`;
+
   /* language=js */
-  `(function() {
-  var defaultMode = '${defaultMode}';
-  var respectPrefersColorScheme = ${respectPrefersColorScheme};
+  return `(function() {
+    var defaultMode = '${defaultMode}';
+    var respectPrefersColorScheme = ${respectPrefersColorScheme};
 
-  function setDataThemeAttribute(theme) {
-    document.documentElement.setAttribute('data-theme', theme);
-  }
+    function setDataThemeAttribute(theme) {
+      document.documentElement.setAttribute('data-theme', theme);
+    }
 
-  function getQueryStringTheme() {
-    try {
-      return new URLSearchParams(window.location.search).get('${ThemeQueryStringKey}')
-    } catch(e) {}
-  }
+    function getQueryStringTheme() {
+      try {
+        return new URLSearchParams(window.location.search).get('${ThemeQueryStringKey}')
+      } catch (e) {
+      }
+    }
 
-  function getStoredTheme() {
-    try {
-      return localStorage.getItem('${ThemeStorageKey}');
-    } catch (err) {}
-  }
+    function getStoredTheme() {
+      try {
+        return window['${siteStorage.type}'].getItem('${themeStorageKey}');
+      } catch (err) {
+      }
+    }
 
-  var initialTheme = getQueryStringTheme() || getStoredTheme();
-  if (initialTheme !== null) {
-    setDataThemeAttribute(initialTheme);
-  } else {
-    if (
-      respectPrefersColorScheme &&
-      window.matchMedia('(prefers-color-scheme: dark)').matches
-    ) {
-      setDataThemeAttribute('dark');
-    } else if (
-      respectPrefersColorScheme &&
-      window.matchMedia('(prefers-color-scheme: light)').matches
-    ) {
-      setDataThemeAttribute('light');
+    var initialTheme = getQueryStringTheme() || getStoredTheme();
+    if (initialTheme !== null) {
+      setDataThemeAttribute(initialTheme);
     } else {
-      setDataThemeAttribute(defaultMode === 'dark' ? 'dark' : 'light');
+      if (
+        respectPrefersColorScheme &&
+        window.matchMedia('(prefers-color-scheme: dark)').matches
+      ) {
+        setDataThemeAttribute('dark');
+      } else if (
+        respectPrefersColorScheme &&
+        window.matchMedia('(prefers-color-scheme: light)').matches
+      ) {
+        setDataThemeAttribute('light');
+      } else {
+        setDataThemeAttribute(defaultMode === 'dark' ? 'dark' : 'light');
+      }
     }
-  }
-})();`;
+  })();`;
+};
 
 /* language=js */
 const DataAttributeQueryStringInlineJavaScript = `
@@ -126,6 +134,7 @@ export default function themeClassic(
 ): Plugin<undefined> {
   const {
     i18n: {currentLocale, localeConfigs},
+    siteStorage,
   } = context;
   const themeConfig = context.siteConfig.themeConfig as ThemeConfig;
   const {
@@ -218,7 +227,7 @@ export default function themeClassic(
           {
             tagName: 'script',
             innerHTML: `
-${noFlashColorMode(colorMode)}
+${noFlashColorMode({colorMode, siteStorage})}
 ${DataAttributeQueryStringInlineJavaScript}
 ${announcementBar ? AnnouncementBarInlineJavaScript : ''}
             `,

packages/docusaurus-theme-common/src/utils/storageUtils.ts

@@ -6,12 +6,15 @@
  */
 
 import {useCallback, useRef, useSyncExternalStore} from 'react';
+import SiteStorage from '@generated/site-storage';
 
-const StorageTypes = ['localStorage', 'sessionStorage', 'none'] as const;
+export type StorageType = (typeof SiteStorage)['type'] | 'none';
 
-export type StorageType = (typeof StorageTypes)[number];
+const DefaultStorageType: StorageType = SiteStorage.type;
 
-const DefaultStorageType: StorageType = 'localStorage';
+function applyNamespace(storageKey: string): string {
+  return `${storageKey}${SiteStorage.namespace}`;
+}
 
 // window.addEventListener('storage') only works for different windows...
 // so for current window we have to dispatch the event manually
@@ -134,9 +137,10 @@ Please only call storage APIs in effects and event handlers.`);
  * this API can be a no-op. See also https://github.com/facebook/docusaurus/issues/6036
  */
 export function createStorageSlot(
-  key: string,
+  keyInput: string,
   options?: {persistence?: StorageType},
 ): StorageSlot {
+  const key = applyNamespace(keyInput);
   if (typeof window === 'undefined') {
     return createServerStorageSlot(key);
   }

packages/docusaurus-types/src/config.d.ts

@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import type {SiteStorage} from './context';
 import type {RuleSetRule} from 'webpack';
 import type {Required as RequireKeys, DeepPartial} from 'utility-types';
 import type {I18nConfig} from './i18n';
@@ -115,6 +116,15 @@ export type MarkdownConfig = {
   anchors: MarkdownAnchorsConfig;
 };
 
+export type StorageConfig = {
+  type: SiteStorage['type'];
+  namespace: boolean | string;
+};
+
+export type FutureConfig = {
+  experimental_storage: StorageConfig;
+};
+
 /**
  * Docusaurus config, after validation/normalization.
  */
@@ -171,6 +181,11 @@ export type DocusaurusConfig = {
    * @see https://docusaurus.io/docs/api/docusaurus-config#i18n
    */
   i18n: I18nConfig;
+  /**
+   * Docusaurus future flags and experimental features.
+   * Similar to Remix future flags, see https://remix.run/blog/future-flags
+   */
+  future: FutureConfig;
   /**
    * This option adds `<meta name="robots" content="noindex, nofollow">` to
    * every page to tell search engines to avoid indexing your site.

packages/docusaurus-types/src/context.d.ts

@@ -27,6 +27,25 @@ export type SiteMetadata = {
   readonly pluginVersions: {[pluginName: string]: PluginVersionInformation};
 };
 
+export type SiteStorage = {
+  /**
+   * Which browser storage do you want to use?
+   * Between "localStorage" and "sessionStorage".
+   * The default is "localStorage".
+   */
+  type: 'localStorage' | 'sessionStorage';
+
+  /**
+   * Applies a namespace to the theme storage key
+   * For readability, the namespace is applied at the end of the key
+   * The final storage key will be = `${key}${namespace}`
+   *
+   * The default namespace is "" for retro-compatibility reasons
+   * If you want a separator, the namespace should contain it ("-myNamespace")
+   */
+  namespace: string;
+};
+
 export type GlobalData = {[pluginName: string]: {[pluginId: string]: unknown}};
 
 export type LoadContext = {
@@ -50,6 +69,11 @@ export type LoadContext = {
   baseUrl: string;
   i18n: I18n;
   codeTranslations: CodeTranslations;
+
+  /**
+   * Defines the default browser storage behavior for a site
+   */
+  siteStorage: SiteStorage;
 };
 
 export type Props = LoadContext & {

packages/docusaurus-types/src/index.d.ts

@@ -12,6 +12,8 @@ export {
   DefaultParseFrontMatter,
   ParseFrontMatter,
   DocusaurusConfig,
+  FutureConfig,
+  StorageConfig,
   Config,
 } from './config';
 
@@ -20,6 +22,7 @@ export {
   DocusaurusContext,
   GlobalData,
   LoadContext,
+  SiteStorage,
   Props,
 } from './context';
 

packages/docusaurus/src/server/__tests__/__snapshots__/config.test.ts.snap

@@ -7,6 +7,12 @@ exports[`loadSiteConfig website with .cjs siteConfig 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -61,6 +67,12 @@ exports[`loadSiteConfig website with ts + js config 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -115,6 +127,12 @@ exports[`loadSiteConfig website with valid JS CJS config 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -169,6 +187,12 @@ exports[`loadSiteConfig website with valid JS ESM config 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -223,6 +247,12 @@ exports[`loadSiteConfig website with valid TypeScript CJS config 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -277,6 +307,12 @@ exports[`loadSiteConfig website with valid TypeScript ESM config 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -331,6 +367,12 @@ exports[`loadSiteConfig website with valid async config 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -387,6 +429,12 @@ exports[`loadSiteConfig website with valid async config creator function 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -443,6 +491,12 @@ exports[`loadSiteConfig website with valid config creator function 1`] = `
     "baseUrlIssueBanner": true,
     "clientModules": [],
     "customFields": {},
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",
@@ -502,6 +556,12 @@ exports[`loadSiteConfig website with valid siteConfig 1`] = `
     ],
     "customFields": {},
     "favicon": "img/docusaurus.ico",
+    "future": {
+      "experimental_storage": {
+        "namespace": false,
+        "type": "localStorage",
+      },
+    },
     "headTags": [],
     "i18n": {
       "defaultLocale": "en",