facebook · slorber · Mar 18, 2022 · Mar 17, 2022 · Mar 17, 2022 · Mar 17, 2022
@@ -246,6 +246,12 @@ declare module '@docusaurus/useDocusaurusContext' {
   export default function useDocusaurusContext(): DocusaurusContext;
 }
 
+declare module '@docusaurus/useRouteContext' {
+  import type {PluginRouteContext} from '@docusaurus/types';
+
+  export default function useRouteContext(): PluginRouteContext;
+}
+
 declare module '@docusaurus/useIsBrowser' {
   export default function useIsBrowser(): boolean;
 }

@@ -191,6 +191,7 @@ declare module '@theme/DocItem' {
   };
 
   export type Metadata = {
+    readonly unversionedId?: string;
     readonly description?: string;
     readonly title?: string;
     readonly permalink?: string;

@@ -17,7 +17,11 @@ import TOC from '@theme/TOC';
 import TOCCollapsible from '@theme/TOCCollapsible';
 import Heading from '@theme/Heading';
 import styles from './styles.module.css';
-import {ThemeClassNames, useWindowSize} from '@docusaurus/theme-common';
+import {
+  HtmlClassNameProvider,
+  ThemeClassNames,
+  useWindowSize,
+} from '@docusaurus/theme-common';
 import DocBreadcrumbs from '@theme/DocBreadcrumbs';
 import MDXContent from '@theme/MDXContent';
 
@@ -49,7 +53,7 @@ export default function DocItem(props: Props): JSX.Element {
     canRenderTOC && (windowSize === 'desktop' || windowSize === 'ssr');
 
   return (
-    <>
+    <HtmlClassNameProvider className={`docs-doc-id-${metadata.unversionedId}`}>
       <Seo {...{title, description, keywords, image}} />
 
       <div className="row">
@@ -107,6 +111,6 @@ export default function DocItem(props: Props): JSX.Element {
           </div>
         )}
       </div>
-    </>
+    </HtmlClassNameProvider>
   );
 }
@@ -20,14 +20,15 @@ import {translate} from '@docusaurus/Translate';
 
 import clsx from 'clsx';
 import styles from './styles.module.css';
+
 import {
+  HtmlClassNameProvider,
   ThemeClassNames,
   docVersionSearchTag,
   DocsSidebarProvider,
   useDocsSidebar,
   DocsVersionProvider,
 } from '@docusaurus/theme-common';
-import Head from '@docusaurus/Head';
 
 type DocPageContentProps = {
   readonly currentDocRoute: DocumentRoute;
@@ -160,11 +161,7 @@ export default function DocPage(props: Props): JSX.Element {
     : null;
 
   return (
-    <>
-      <Head>
-        {/* TODO we should add a core addRoute({htmlClassName}) action */}
-        <html className={versionMetadata.className} />
-      </Head>
+    <HtmlClassNameProvider className={versionMetadata.className}>
       <DocsVersionProvider version={versionMetadata}>
         <DocsSidebarProvider sidebar={sidebar ?? null}>
           <DocPageContent
@@ -175,6 +172,6 @@ export default function DocPage(props: Props): JSX.Element {
           </DocPageContent>
         </DocsSidebarProvider>
       </DocsVersionProvider>
-    </>
+    </HtmlClassNameProvider>
   );
 }
@@ -13,6 +13,7 @@ import {
   DocsPreferredVersionContextProvider,
   MobileSecondaryMenuProvider,
   ScrollControllerProvider,
+  PluginHtmlClassNameProvider,
 } from '@docusaurus/theme-common';
 import type {Props} from '@theme/LayoutProviders';
 
@@ -24,7 +25,9 @@ export default function LayoutProviders({children}: Props): JSX.Element {
           <ScrollControllerProvider>
             <DocsPreferredVersionContextProvider>
               <MobileSecondaryMenuProvider>
-                {children}
+                <PluginHtmlClassNameProvider>
+                  {children}
+                </PluginHtmlClassNameProvider>
               </MobileSecondaryMenuProvider>
             </DocsPreferredVersionContextProvider>
           </ScrollControllerProvider>

@@ -135,6 +135,11 @@ export {isRegexpStringMatch} from './utils/regexpUtils';
 
 export {useHomePageRoute} from './utils/routesUtils';
 
+export {
+  HtmlClassNameProvider,
+  PluginHtmlClassNameProvider,
+} from './utils/metadataUtilsTemp';
+
 export {useColorMode, ColorModeProvider} from './utils/colorModeUtils';
 export {
   useTabGroupChoice,

@@ -0,0 +1,56 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import React, {type ReactNode} from 'react';
+import Head from '@docusaurus/Head';
+import clsx from 'clsx';
+import useRouteContext from '@docusaurus/useRouteContext';
+
+const HtmlClassNameContext = React.createContext<string | undefined>(undefined);
+
+// This wrapper is necessary because Helmet does not "merge" classes
+// See https://github.com/staylor/react-helmet-async/issues/161
+export function HtmlClassNameProvider({
+  className: classNameProp,
+  children,
+}: {
+  className: string;
+  children: ReactNode;
+}): JSX.Element {
+  const classNameContext = React.useContext(HtmlClassNameContext);
+  const className = clsx(classNameContext, classNameProp);
+  return (
+    <HtmlClassNameContext.Provider value={className}>
+      <Head>
+        <html className={className} />
+      </Head>
+      {children}
+    </HtmlClassNameContext.Provider>
+  );
+}
+
+function pluginNameToClassName(pluginName: string) {
+  return `plugin-${pluginName.replace(
+    /docusaurus-(?:plugin|theme)-(?:content-)?/gi,
+    '',
+  )}`;
+}
+
+export function PluginHtmlClassNameProvider({
+  children,
+}: {
+  children: ReactNode;
+}): JSX.Element {
+  const routeContext = useRouteContext();
+  const nameClass = pluginNameToClassName(routeContext.plugin.name);
+  const idClass = `plugin-id-${routeContext.plugin.id}`;
+  return (
+    <HtmlClassNameProvider className={clsx(nameClass, idClass)}>
+      {children}
+    </HtmlClassNameProvider>
+  );
+}
@@ -377,6 +377,24 @@ export interface RouteConfig {
   [propName: string]: unknown;
 }
 
+export interface RouteContext {
+  /**
+   * Plugin-specific context data.
+   */
+  data?: object | undefined;
+}
+
+/**
+ * Top-level plugin routes automatically add some context data to the route.
+ * This permits us to know which plugin is handling the current route.
+ */
+export interface PluginRouteContext extends RouteContext {
+  plugin: {
+    id: string;
+    name: string;
+  };
+}
+
 export type Route = {
   readonly path: string;
   readonly component: ReturnType<typeof Loadable>;

@@ -11,6 +11,7 @@ import Loading from '@theme/Loading';
 import routesChunkNames from '@generated/routesChunkNames';
 import registry from '@generated/registry';
 import flat from '../flat';
+import {RouteContextProvider} from '../routeContext';
 
 type OptsLoader = Record<string, typeof registry[keyof typeof registry][0]>;
 
@@ -22,7 +23,16 @@ export default function ComponentCreator(
   if (path === '*') {
     return Loadable({
       loading: Loading,
-      loader: () => import('@theme/NotFound'),
+      loader: async () => {
+        const NotFound = (await import('@theme/NotFound')).default;
+        return (props) => (
+          // Is there a better API for this?
+          <RouteContextProvider
+            value={{plugin: {name: 'native', id: 'default'}}}>
+            <NotFound {...(props as never)} />
+          </RouteContextProvider>
+        );
+      },
     });
   }
 
@@ -84,7 +94,18 @@ export default function ComponentCreator(
 
       const Component = loadedModules.component;
       delete loadedModules.component;
-      return <Component {...loadedModules} {...props} />;
+
+      /* eslint-disable no-underscore-dangle */
+      const routeContextModule = loadedModules.__routeContextModule;
+      delete loadedModules.__routeContextModule;
+      /* eslint-enable no-underscore-dangle */
+
+      // Is there any way to put this RouteContextProvider upper in the tree?
+      return (
+        <RouteContextProvider value={routeContextModule}>
+          <Component {...loadedModules} {...props} />;
+        </RouteContextProvider>
+      );
     },
   });
 }
@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import React from 'react';
+import type {PluginRouteContext} from '@docusaurus/types';
+import {Context} from '../routeContext';
+
+export default function useRouteContext(): PluginRouteContext {
+  const context = React.useContext(Context);
+  if (!context) {
+    throw new Error(
+      'Unexpected: no Docusaurus parent/current route context found',
+    );
+  }
+  return context;
+}
@@ -0,0 +1,58 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import React, {useMemo, type ReactNode} from 'react';
+import type {PluginRouteContext, RouteContext} from '@docusaurus/types';
+
+export const Context = React.createContext<PluginRouteContext | null>(null);
+
+function mergeContexts({
+  parent,
+  value,
+}: {
+  parent: PluginRouteContext | null;
+  value: RouteContext | null;
+}): PluginRouteContext {
+  if (!parent) {
+    if (!value) {
+      throw new Error(
+        'Unexpected: no Docusaurus parent/current route context found',
+      );
+    } else if (!('plugin' in value)) {
+      throw new Error(
+        'Unexpected: Docusaurus parent route context has no plugin attribute',
+      );
+    }
+    return value;
+  }
+
+  // TODO deep merge this
+  const data = {...parent.data, ...value?.data};
+
+  return {
+    // nested routes are not supposed to override plugin attribute
+    plugin: parent.plugin,
+    data,
+  };
+}
+
+export function RouteContextProvider({
+  children,
+  value,
+}: {
+  children: ReactNode;
+  value: PluginRouteContext | null;
+}): JSX.Element {
+  const parent = React.useContext(Context);
+
+  const mergedValue = useMemo(
+    () => mergeContexts({parent, value}),
+    [parent, value],
+  );
+
+  return <Context.Provider value={mergedValue}>{children}</Context.Provider>;
+}
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {generate} from '@docusaurus/utils';
+import {docuHash, generate} from '@docusaurus/utils';
 import fs from 'fs-extra';
 import path from 'path';
 import type {
@@ -18,6 +18,7 @@ import type {
   ThemeConfig,
   LoadedPlugin,
   InitializedPlugin,
+  PluginRouteContext,
 } from '@docusaurus/types';
 import initPlugins from './init';
 import logger from '@docusaurus/logger';
@@ -149,17 +150,6 @@ export async function loadPlugins({
         const dataDirRoot = path.join(context.generatedFilesDir, plugin.name);
         const dataDir = path.join(dataDirRoot, pluginId);
 
-        const addRoute: PluginContentLoadedActions['addRoute'] = (
-          initialRouteConfig,
-        ) => {
-          // Trailing slash behavior is handled in a generic way for all plugins
-          const finalRouteConfig = applyRouteTrailingSlash(initialRouteConfig, {
-            trailingSlash: context.siteConfig.trailingSlash,
-            baseUrl: context.siteConfig.baseUrl,
-          });
-          pluginsRouteConfigs.push(finalRouteConfig);
-        };
-
         const createData: PluginContentLoadedActions['createData'] = async (
           name,
           data,
@@ -170,6 +160,34 @@ export async function loadPlugins({
           return modulePath;
         };
 
+        // TODO this would be better to do all that in the codegen phase
+        // TODO handle context for nested routes
+        const pluginRouteContext: PluginRouteContext = {
+          plugin: {name: plugin.name, id: pluginId},
+          data: undefined, // TODO allow plugins to provide context data
+        };
+        const pluginRouteContextModulePath = await createData(
+          `${docuHash('pluginRouteContextModule')}.json`,
+          JSON.stringify(pluginRouteContext, null, 2),
+        );
+
+        const addRoute: PluginContentLoadedActions['addRoute'] = (
+          initialRouteConfig,
+        ) => {
+          // Trailing slash behavior is handled in a generic way for all plugins
+          const finalRouteConfig = applyRouteTrailingSlash(initialRouteConfig, {
+            trailingSlash: context.siteConfig.trailingSlash,
+            baseUrl: context.siteConfig.baseUrl,
+          });
+          pluginsRouteConfigs.push({
+            ...finalRouteConfig,
+            modules: {
+              ...finalRouteConfig.modules,
+              __routeContextModule: pluginRouteContextModulePath,
+            },
+          });
+        };
+
         // the plugins global data are namespaced to avoid data conflicts:
         // - by plugin name
         // - by plugin id (allow using multiple instances of the same plugin)