feat: allow custom navbarItem types to pass through validation

packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.ts

@@ -227,6 +227,44 @@ describe('themeConfig', () => {
     });
   });
 
+  it('accept "custom-" prefixed custom navbar item type', () => {
+    const config = {
+      navbar: {
+        items: [
+          {
+            type: 'custom-x',
+            position: 'left',
+            xyz: 42,
+          },
+          {
+            label: 'Dropdown with custom item',
+            position: 'right',
+            items: [
+              {
+                label: 'Facebook',
+                href: 'https://.facebook.com/',
+                target: '_self',
+              },
+              {
+                type: 'custom-y',
+                any: new Date(),
+                prop: 42,
+                isAccepted: true,
+              },
+            ],
+          },
+        ],
+      },
+    };
+    expect(testValidateThemeConfig(config)).toEqual({
+      ...DEFAULT_CONFIG,
+      navbar: {
+        ...DEFAULT_CONFIG.navbar,
+        ...config.navbar,
+      },
+    });
+  });
+
   it('rejects unknown navbar item type', () => {
     const config = {
       navbar: {

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

@@ -893,6 +893,37 @@ declare module '@theme/NavbarItem/HtmlNavbarItem' {
   export default function HtmlNavbarItem(props: Props): JSX.Element;
 }
 
+declare module '@theme/NavbarItem/ComponentTypes' {
+  import type {ComponentType} from 'react';
+
+  import type DefaultNavbarItem from '@theme/NavbarItem/DefaultNavbarItem';
+  import type DropdownNavbarItem from '@theme/NavbarItem/DropdownNavbarItem';
+  import type LocaleDropdownNavbarItem from '@theme/NavbarItem/LocaleDropdownNavbarItem';
+  import type SearchNavbarItem from '@theme/NavbarItem/SearchNavbarItem';
+  import type HtmlNavbarItem from '@theme/NavbarItem/HtmlNavbarItem';
+  import type DocNavbarItem from '@theme/NavbarItem/DocNavbarItem';
+  import type DocSidebarNavbarItem from '@theme/NavbarItem/DocSidebarNavbarItem';
+  import type DocsVersionNavbarItem from '@theme/NavbarItem/DocsVersionNavbarItem';
+  import type DocsVersionDropdownNavbarItem from '@theme/NavbarItem/DocsVersionDropdownNavbarItem';
+
+  export type ComponentTypesObject = {
+    readonly default: typeof DefaultNavbarItem;
+    readonly localeDropdown: typeof LocaleDropdownNavbarItem;
+    readonly search: typeof SearchNavbarItem;
+    readonly dropdown: typeof DropdownNavbarItem;
+    readonly html: typeof HtmlNavbarItem;
+    readonly doc: typeof DocNavbarItem;
+    readonly docSidebar: typeof DocSidebarNavbarItem;
+    readonly docsVersion: typeof DocsVersionNavbarItem;
+    readonly docsVersionDropdown: typeof DocsVersionDropdownNavbarItem;
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    [customComponentType: string]: ComponentType<any>;
+  };
+
+  const ComponentTypes: ComponentTypesObject;
+  export default ComponentTypes;
+}
+
 declare module '@theme/NavbarItem' {
   import type {ComponentProps} from 'react';
   import type {Props as DefaultNavbarItemProps} from '@theme/NavbarItem/DefaultNavbarItem';

packages/docusaurus-theme-classic/src/theme/NavbarItem/ComponentTypes.tsx

@@ -0,0 +1,32 @@
+/**
+ * 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 DefaultNavbarItem from '@theme/NavbarItem/DefaultNavbarItem';
+import DropdownNavbarItem from '@theme/NavbarItem/DropdownNavbarItem';
+import LocaleDropdownNavbarItem from '@theme/NavbarItem/LocaleDropdownNavbarItem';
+import SearchNavbarItem from '@theme/NavbarItem/SearchNavbarItem';
+import HtmlNavbarItem from '@theme/NavbarItem/HtmlNavbarItem';
+import DocNavbarItem from '@theme/NavbarItem/DocNavbarItem';
+import DocSidebarNavbarItem from '@theme/NavbarItem/DocSidebarNavbarItem';
+import DocsVersionNavbarItem from '@theme/NavbarItem/DocsVersionNavbarItem';
+import DocsVersionDropdownNavbarItem from '@theme/NavbarItem/DocsVersionDropdownNavbarItem';
+
+import type {ComponentTypesObject} from '@theme/NavbarItem/ComponentTypes';
+
+const ComponentTypes: ComponentTypesObject = {
+  default: DefaultNavbarItem,
+  localeDropdown: LocaleDropdownNavbarItem,
+  search: SearchNavbarItem,
+  dropdown: DropdownNavbarItem,
+  html: HtmlNavbarItem,
+  doc: DocNavbarItem,
+  docSidebar: DocSidebarNavbarItem,
+  docsVersion: DocsVersionNavbarItem,
+  docsVersionDropdown: DocsVersionDropdownNavbarItem,
+};
+
+export default ComponentTypes;

packages/docusaurus-theme-classic/src/theme/NavbarItem/index.tsx

@@ -6,57 +6,26 @@
  */
 
 import React from 'react';
-import DefaultNavbarItem from '@theme/NavbarItem/DefaultNavbarItem';
-import DropdownNavbarItem, {
-  type Props as DropdownNavbarItemProps,
-} from '@theme/NavbarItem/DropdownNavbarItem';
-import LocaleDropdownNavbarItem from '@theme/NavbarItem/LocaleDropdownNavbarItem';
-import SearchNavbarItem from '@theme/NavbarItem/SearchNavbarItem';
-import HtmlNavbarItem from '@theme/NavbarItem/HtmlNavbarItem';
+import {type Props as DropdownNavbarItemProps} from '@theme/NavbarItem/DropdownNavbarItem';
 import type {Types, Props} from '@theme/NavbarItem';
 
-const NavbarItemComponents: {
-  // Not really worth typing, as we pass all props down immediately
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  [type in Exclude<Types, undefined>]: () => (props: any) => JSX.Element;
-} = {
-  default: () => DefaultNavbarItem,
-  localeDropdown: () => LocaleDropdownNavbarItem,
-  search: () => SearchNavbarItem,
-  dropdown: () => DropdownNavbarItem,
-  html: () => HtmlNavbarItem,
+import ComponentTypes from '@theme/NavbarItem/ComponentTypes';
 
-  // Need to lazy load these items as we don't know for sure the docs plugin is
-  // loaded. See https://github.com/facebook/docusaurus/issues/3360
-  /* eslint-disable @typescript-eslint/no-var-requires, global-require */
-  docsVersion: () => require('@theme/NavbarItem/DocsVersionNavbarItem').default,
-  docsVersionDropdown: () =>
-    require('@theme/NavbarItem/DocsVersionDropdownNavbarItem').default,
-  doc: () => require('@theme/NavbarItem/DocNavbarItem').default,
-  docSidebar: () => require('@theme/NavbarItem/DocSidebarNavbarItem').default,
-  /* eslint-enable @typescript-eslint/no-var-requires, global-require */
-} as const;
-
-type NavbarItemComponentType = keyof typeof NavbarItemComponents;
-
-const getNavbarItemComponent = (type: NavbarItemComponentType) => {
-  const navbarItemComponentFn = NavbarItemComponents[type];
-  if (!navbarItemComponentFn) {
+const getNavbarItemComponent = (type: NonNullable<Types>) => {
+  const component = ComponentTypes[type];
+  if (!component) {
     throw new Error(`No NavbarItem component found for type "${type}".`);
   }
-  return navbarItemComponentFn();
+  return component;
 };
 
-function getComponentType(
-  type: Types,
-  isDropdown: boolean,
-): NavbarItemComponentType {
+function getComponentType(type: Types, isDropdown: boolean) {
   // Backward compatibility: navbar item with no type set
   // but containing dropdown items should use the type "dropdown"
   if (!type || type === 'default') {
     return isDropdown ? 'dropdown' : 'default';
   }
-  return type as NavbarItemComponentType;
+  return type as NonNullable<Types>;
 }
 
 export default function NavbarItem({type, ...props}: Props): JSX.Element {
@@ -65,5 +34,6 @@ export default function NavbarItem({type, ...props}: Props): JSX.Element {
     (props as DropdownNavbarItemProps).items !== undefined,
   );
   const NavbarItemComponent = getNavbarItemComponent(componentType);
+  // @ts-expect-error: how to type this?
   return <NavbarItemComponent {...props} />;
 }

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

@@ -99,11 +99,22 @@ const HtmlNavbarItemSchema = Joi.object({
   value: Joi.string().required(),
 });
 
-const itemWithType = (type: string | undefined) => {
+// A temporary workaround to allow users to add custom navbar items
+// See https://github.com/facebook/docusaurus/issues/7227
+const CustomNavbarItemRegexp = /custom-.*/;
+const CustomNavbarItemSchema = Joi.object({
+  type: Joi.string().regex(CustomNavbarItemRegexp).required(),
+}).unknown();
+
+const itemWithType = (type: string | RegExp | undefined) => {
   // Because equal(undefined) is not supported :/
-  const typeSchema = type
-    ? Joi.string().required().equal(type)
-    : Joi.string().forbidden();
+  const typeSchema =
+    // eslint-disable-next-line no-nested-ternary
+    type instanceof RegExp
+      ? Joi.string().required().regex(type)
+      : type
+      ? Joi.string().required().equal(type)
+      : Joi.string().forbidden();
   return Joi.object({
     type: typeSchema,
   })
@@ -135,6 +146,10 @@ const DropdownSubitemSchema = Joi.object({
       is: itemWithType('html'),
       then: HtmlNavbarItemSchema,
     },
+    {
+      is: itemWithType(CustomNavbarItemRegexp),
+      then: CustomNavbarItemSchema,
+    },
     {
       is: Joi.alternatives().try(
         itemWithType('dropdown'),
@@ -210,6 +225,10 @@ const NavbarItemSchema = Joi.object({
       is: itemWithType('html'),
       then: HtmlNavbarItemSchema,
     },
+    {
+      is: itemWithType(CustomNavbarItemRegexp),
+      then: CustomNavbarItemSchema,
+    },
     {
       is: itemWithType(undefined),
       then: Joi.object().when('.', {

website/docusaurus.config.js

@@ -409,12 +409,18 @@ const config = {
             position: 'left',
             activeBaseRegex: `/community/`,
           },
+          // This item links to a draft doc: only displayed in dev
           {
             type: 'doc',
             docId: 'test-draft',
             label: 'Tests',
             docsPluginId: 'docs-tests',
           },
+          // Custom item for dogfooding: only displayed in /tests/ routes
+          {
+            type: 'custom-dogfood-navbar-item',
+            content: '😉',
+          },
           // Right
           {
             type: 'docsVersionDropdown',

website/src/components/NavbarItems/CustomDogfoodNavbarItem.tsx

@@ -0,0 +1,33 @@
+/**
+ * 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 {useLocation} from '@docusaurus/router';
+
+// used to dogfood custom navbar elements are possible
+// see https://github.com/facebook/docusaurus/issues/7227
+export default function CustomDogfoodNavbarItem(props: {
+  content: string;
+  mobile?: boolean;
+}): JSX.Element | null {
+  const {pathname} = useLocation();
+  const shouldRender = pathname.includes('/tests/');
+  if (!shouldRender) {
+    return null;
+  }
+  return (
+    <button
+      onClick={() => {
+        // eslint-disable-next-line no-alert
+        alert("I'm a custom navbar item type example");
+      }}
+      type="button">
+      {props.content}
+      {props.mobile ? ' (mobile)' : ''}
+    </button>
+  );
+}

website/src/theme/NavbarItem/ComponentTypes.tsx

@@ -0,0 +1,14 @@
+/**
+ * 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 ComponentTypes from '@theme-original/NavbarItem/ComponentTypes';
+import CustomDogfoodNavbarItem from '@site/src/components/NavbarItems/CustomDogfoodNavbarItem';
+
+export default {
+  ...ComponentTypes,
+  'custom-dogfood-navbar-item': CustomDogfoodNavbarItem,
+};