diff --git a/jest.config.mjs b/jest.config.mjs
index 4c21dede96..2b0342501b 100644
--- a/jest.config.mjs
+++ b/jest.config.mjs
@@ -36,18 +36,18 @@ export default {
     // Jest can't resolve CSS or asset imports
     '^.+\\.(css|jpe?g|png|svg)$': '<rootDir>/jest/emptyModule.js',
 
-    // TODO we need to allow Jest to resolve core Webpack aliases automatically
+    // Using src instead of lib, so we always get fresh source
     '@docusaurus/(browserContext|BrowserOnly|ComponentCreator|constants|docusaurusContext|ExecutionEnvironment|Head|Interpolate|isInternalUrl|Link|Noop|renderRoutes|router|Translate|use.*)':
-      '@docusaurus/core/lib/client/exports/$1',
+      '@docusaurus/core/src/client/exports/$1',
     // Maybe point to a fixture?
     '@generated/.*': '<rootDir>/jest/emptyModule.js',
     // TODO use "projects" + multiple configs if we work on another theme?
     '@theme/(.*)': '@docusaurus/theme-classic/src/theme/$1',
     '@site/(.*)': 'website/$1',
 
-    // TODO why Jest can't figure node package entry points?
+    // Using src instead of lib, so we always get fresh source
     '@docusaurus/plugin-content-docs/client':
-      '@docusaurus/plugin-content-docs/lib/client/index.js',
+      '@docusaurus/plugin-content-docs/src/client/index.ts',
   },
   globals: {
     window: {
diff --git a/packages/docusaurus-mdx-loader/src/remark/toc/__tests__/__fixtures__/just-content.md b/packages/docusaurus-mdx-loader/src/remark/toc/__tests__/__fixtures__/just-content.md
index 982f2df656..7f9152f5b8 100644
--- a/packages/docusaurus-mdx-loader/src/remark/toc/__tests__/__fixtures__/just-content.md
+++ b/packages/docusaurus-mdx-loader/src/remark/toc/__tests__/__fixtures__/just-content.md
@@ -13,3 +13,5 @@ Lorem ipsum
 Some content here
 
 ## I ♥ unicode.
+
+export const c = 1;
diff --git a/packages/docusaurus-mdx-loader/src/remark/toc/__tests__/__snapshots__/index.test.ts.snap b/packages/docusaurus-mdx-loader/src/remark/toc/__tests__/__snapshots__/index.test.ts.snap
index bb2f9b0723..fbd3fcc125 100644
--- a/packages/docusaurus-mdx-loader/src/remark/toc/__tests__/__snapshots__/index.test.ts.snap
+++ b/packages/docusaurus-mdx-loader/src/remark/toc/__tests__/__snapshots__/index.test.ts.snap
@@ -114,6 +114,8 @@ Lorem ipsum
 Some content here
 
 ## I ♥ unicode.
+
+export const c = 1;
 "
 `;
 
@@ -241,5 +243,7 @@ Lorem ipsum
 Some content here
 
 ## I ♥ unicode.
+
+export const c = 1;
 "
 `;
diff --git a/packages/docusaurus-mdx-loader/src/remark/utils/index.ts b/packages/docusaurus-mdx-loader/src/remark/utils/index.ts
index e735eea28e..b0314d7a23 100644
--- a/packages/docusaurus-mdx-loader/src/remark/utils/index.ts
+++ b/packages/docusaurus-mdx-loader/src/remark/utils/index.ts
@@ -31,7 +31,6 @@ export function toValue(node: PhrasingContent | Heading): string {
     case 'link':
       return stringifyContent(node);
     default:
+      return toString(node);
   }
-
-  return toString(node);
 }
diff --git a/packages/docusaurus-plugin-client-redirects/src/normalizePluginOptions.ts b/packages/docusaurus-plugin-client-redirects/src/normalizePluginOptions.ts
index f3d2cfb82a..b838746e1e 100644
--- a/packages/docusaurus-plugin-client-redirects/src/normalizePluginOptions.ts
+++ b/packages/docusaurus-plugin-client-redirects/src/normalizePluginOptions.ts
@@ -31,7 +31,7 @@ const RedirectPluginOptionValidation = Joi.object<RedirectOption>({
 const isString = Joi.string().required().not(null);
 
 const UserOptionsSchema = Joi.object<UserPluginOptions>({
-  id: Joi.string().optional(), // TODO remove once validation  migrated to new system
+  id: Joi.string().optional(), // TODO remove once validation migrated to new system
   fromExtensions: Joi.array().items(isString),
   toExtensions: Joi.array().items(isString),
   redirects: Joi.array().items(RedirectPluginOptionValidation),
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/globalData.test.ts.snap b/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/globalData.test.ts.snap
new file mode 100644
index 0000000000..95ed78b3ff
--- /dev/null
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/globalData.test.ts.snap
@@ -0,0 +1,43 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`toGlobalDataVersion generates the right docs, sidebars, and metadata 1`] = `
+Object {
+  "docs": Array [
+    Object {
+      "id": "main",
+      "path": "/current/main",
+      "sidebar": "tutorial",
+    },
+    Object {
+      "id": "doc",
+      "path": "/current/doc",
+      "sidebar": "tutorial",
+    },
+    Object {
+      "id": "/current/generated",
+      "path": "/current/generated",
+      "sidebar": "tutorial",
+    },
+  ],
+  "isLast": true,
+  "label": "Label",
+  "mainDocId": "main",
+  "name": "current",
+  "path": "/current",
+  "sidebars": Object {
+    "another": Object {
+      "link": Object {
+        "label": "Generated",
+        "path": "/current/generated",
+      },
+    },
+    "links": Object {},
+    "tutorial": Object {
+      "link": Object {
+        "label": "main",
+        "path": "/current/main",
+      },
+    },
+  },
+}
+`;
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/globalData.test.ts b/packages/docusaurus-plugin-content-docs/src/__tests__/globalData.test.ts
new file mode 100644
index 0000000000..4c1cac6ecd
--- /dev/null
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/globalData.test.ts
@@ -0,0 +1,100 @@
+/**
+ * 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 {toGlobalDataVersion} from '../globalData';
+
+describe('toGlobalDataVersion', () => {
+  it('generates the right docs, sidebars, and metadata', () => {
+    expect(
+      toGlobalDataVersion({
+        versionName: 'current',
+        versionLabel: 'Label',
+        isLast: true,
+        versionPath: '/current',
+        mainDocId: 'main',
+        docs: [
+          {
+            unversionedId: 'main',
+            permalink: '/current/main',
+            sidebar: 'tutorial',
+          },
+          {
+            unversionedId: 'doc',
+            permalink: '/current/doc',
+            sidebar: 'tutorial',
+          },
+        ],
+        sidebars: {
+          another: [
+            {
+              type: 'category',
+              label: 'Generated',
+              link: {
+                type: 'generated-index',
+                permalink: '/current/generated',
+              },
+              items: [
+                {
+                  type: 'doc',
+                  id: 'doc',
+                },
+              ],
+            },
+          ],
+          tutorial: [
+            {
+              type: 'doc',
+              id: 'main',
+            },
+            {
+              type: 'category',
+              label: 'Generated',
+              link: {
+                type: 'generated-index',
+                permalink: '/current/generated',
+              },
+              items: [
+                {
+                  type: 'doc',
+                  id: 'doc',
+                },
+              ],
+            },
+          ],
+          links: [
+            {
+              type: 'link',
+              href: 'foo',
+              label: 'Foo',
+            },
+            {
+              type: 'link',
+              href: 'bar',
+              label: 'Bar',
+            },
+          ],
+        },
+        categoryGeneratedIndices: [
+          {
+            title: 'Generated',
+            slug: '/current/generated',
+            permalink: '/current/generated',
+            sidebar: 'tutorial',
+          },
+        ],
+        versionBanner: 'unreleased',
+        versionBadge: true,
+        versionClassName: 'current-cls',
+        tagsPath: '/current/tags',
+        contentPath: '',
+        contentPathLocalized: '',
+        sidebarFilePath: '',
+        routePriority: 0.5,
+      }),
+    ).toMatchSnapshot();
+  });
+});
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/slug.test.ts b/packages/docusaurus-plugin-content-docs/src/__tests__/slug.test.ts
index f9f774b693..25ee077dad 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/slug.test.ts
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/slug.test.ts
@@ -111,6 +111,27 @@ describe('getSlug', () => {
     ).toBe('/dir with spâce/hey $hello/my dôc');
   });
 
+  it('throws for invalid routes', () => {
+    expect(() =>
+      getSlug({
+        baseID: 'my dôc',
+        source: '@site/docs/dir with spâce/hey $hello/doc.md',
+        sourceDirName: '/dir with spâce/hey $hello',
+        frontMatterSlug: '//',
+      }),
+    ).toThrowErrorMatchingInlineSnapshot(`
+      "We couldn't compute a valid slug for document with ID \\"my dôc\\" in \\"/dir with spâce/hey $hello\\" directory.
+      The slug we computed looks invalid: //.
+      Maybe your slug front matter is incorrect or there are special characters in the file path?
+      By using front matter to set a custom slug, you should be able to fix this error:
+
+      ---
+      slug: /my/customDocPath
+      ---
+      "
+    `);
+  });
+
   it('handles current dir', () => {
     expect(
       getSlug({baseID: 'doc', source: '@site/docs/doc.md', sourceDirName: '.'}),
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/versions.test.ts b/packages/docusaurus-plugin-content-docs/src/__tests__/versions.test.ts
index 9a4aacb873..9e5f2e4831 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/versions.test.ts
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/versions.test.ts
@@ -26,8 +26,8 @@ const DefaultI18N: I18n = {
   localeConfigs: {},
 };
 
-describe('version paths', () => {
-  it('getVersionsFilePath', () => {
+describe('getVersionsFilePath', () => {
+  it('works', () => {
     expect(getVersionsFilePath('someSiteDir', DEFAULT_PLUGIN_ID)).toBe(
       `someSiteDir${path.sep}versions.json`,
     );
@@ -35,8 +35,10 @@ describe('version paths', () => {
       `otherSite${path.sep}dir${path.sep}pluginId_versions.json`,
     );
   });
+});
 
-  it('getVersionedDocsDirPath', () => {
+describe('getVersionedDocsDirPath', () => {
+  it('works', () => {
     expect(getVersionedDocsDirPath('someSiteDir', DEFAULT_PLUGIN_ID)).toBe(
       `someSiteDir${path.sep}versioned_docs`,
     );
@@ -44,8 +46,10 @@ describe('version paths', () => {
       `otherSite${path.sep}dir${path.sep}pluginId_versioned_docs`,
     );
   });
+});
 
-  it('getVersionedSidebarsDirPath', () => {
+describe('getVersionedSidebarsDirPath', () => {
+  it('works', () => {
     expect(getVersionedSidebarsDirPath('someSiteDir', DEFAULT_PLUGIN_ID)).toBe(
       `someSiteDir${path.sep}versioned_sidebars`,
     );
@@ -55,692 +59,722 @@ describe('version paths', () => {
   });
 });
 
-describe('simple site', () => {
-  async function loadSite() {
-    const simpleSiteDir = path.resolve(
-      path.join(__dirname, '__fixtures__', 'simple-site'),
-    );
-    const defaultOptions: PluginOptions = {
-      id: DEFAULT_PLUGIN_ID,
-      ...DEFAULT_OPTIONS,
-    };
-    const defaultContext = {
-      siteDir: simpleSiteDir,
-      baseUrl: '/',
-      i18n: DefaultI18N,
-    };
+describe('readVersionsMetadata', () => {
+  describe('simple site', () => {
+    async function loadSite() {
+      const simpleSiteDir = path.resolve(
+        path.join(__dirname, '__fixtures__', 'simple-site'),
+      );
+      const defaultOptions: PluginOptions = {
+        id: DEFAULT_PLUGIN_ID,
+        ...DEFAULT_OPTIONS,
+      };
+      const defaultContext = {
+        siteDir: simpleSiteDir,
+        baseUrl: '/',
+        i18n: DefaultI18N,
+      };
 
-    const vCurrent: VersionMetadata = {
-      contentPath: path.join(simpleSiteDir, 'docs'),
-      contentPathLocalized: path.join(
-        simpleSiteDir,
-        'i18n/en/docusaurus-plugin-content-docs/current',
-      ),
-      isLast: true,
-      routePriority: -1,
-      sidebarFilePath: undefined,
-      tagsPath: '/docs/tags',
-      versionLabel: 'Next',
-      versionName: 'current',
-      versionPath: '/docs',
-      versionBanner: null,
-      versionBadge: false,
-      versionClassName: 'docs-version-current',
-    };
-    return {simpleSiteDir, defaultOptions, defaultContext, vCurrent};
-  }
-
-  it('readVersionsMetadata simple site', async () => {
-    const {defaultOptions, defaultContext, vCurrent} = await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: defaultOptions,
-      context: defaultContext,
-    });
-
-    expect(versionsMetadata).toEqual([vCurrent]);
-  });
-
-  it('readVersionsMetadata simple site with base url', async () => {
-    const {defaultOptions, defaultContext, vCurrent} = await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: defaultOptions,
-      context: {
-        ...defaultContext,
-        baseUrl: '/myBaseUrl',
-      },
-    });
-
-    expect(versionsMetadata).toEqual([
-      {
-        ...vCurrent,
-        versionPath: '/myBaseUrl/docs',
-        tagsPath: '/myBaseUrl/docs/tags',
-      },
-    ]);
-  });
-
-  it('readVersionsMetadata simple site with current version config', async () => {
-    const {defaultOptions, defaultContext, vCurrent} = await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: {
-        ...defaultOptions,
-        versions: {
-          current: {
-            label: 'current-label',
-            path: 'current-path',
-          },
-        },
-      },
-      context: {
-        ...defaultContext,
-        baseUrl: '/myBaseUrl',
-      },
-    });
-
-    expect(versionsMetadata).toEqual([
-      {
-        ...vCurrent,
-        versionPath: '/myBaseUrl/docs/current-path',
-        versionLabel: 'current-label',
-        routePriority: undefined,
+      const vCurrent: VersionMetadata = {
+        contentPath: path.join(simpleSiteDir, 'docs'),
+        contentPathLocalized: path.join(
+          simpleSiteDir,
+          'i18n/en/docusaurus-plugin-content-docs/current',
+        ),
+        isLast: true,
+        routePriority: -1,
         sidebarFilePath: undefined,
-        tagsPath: '/myBaseUrl/docs/current-path/tags',
-        versionEditUrl: undefined,
-        versionEditUrlLocalized: undefined,
-      },
-    ]);
-  });
+        tagsPath: '/docs/tags',
+        versionLabel: 'Next',
+        versionName: 'current',
+        versionPath: '/docs',
+        versionBanner: null,
+        versionBadge: false,
+        versionClassName: 'docs-version-current',
+      };
+      return {simpleSiteDir, defaultOptions, defaultContext, vCurrent};
+    }
 
-  it('readVersionsMetadata simple site with unknown lastVersion should throw', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
+    it('works', async () => {
+      const {defaultOptions, defaultContext, vCurrent} = await loadSite();
 
-    await expect(
-      readVersionsMetadata({
-        options: {...defaultOptions, lastVersion: 'unknownVersionName'},
+      const versionsMetadata = await readVersionsMetadata({
+        options: defaultOptions,
         context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"Docs option lastVersion: unknownVersionName is invalid. Available version names are: current"`,
-    );
-  });
+      });
 
-  it('readVersionsMetadata simple site with unknown version configurations should throw', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
+      expect(versionsMetadata).toEqual([vCurrent]);
+    });
 
-    await expect(
-      readVersionsMetadata({
+    it('works with base url', async () => {
+      const {defaultOptions, defaultContext, vCurrent} = await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
+        options: defaultOptions,
+        context: {
+          ...defaultContext,
+          baseUrl: '/myBaseUrl',
+        },
+      });
+
+      expect(versionsMetadata).toEqual([
+        {
+          ...vCurrent,
+          versionPath: '/myBaseUrl/docs',
+          tagsPath: '/myBaseUrl/docs/tags',
+        },
+      ]);
+    });
+
+    it('works with current version config', async () => {
+      const {defaultOptions, defaultContext, vCurrent} = await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
         options: {
           ...defaultOptions,
           versions: {
-            current: {label: 'current'},
-            unknownVersionName1: {label: 'unknownVersionName1'},
-            unknownVersionName2: {label: 'unknownVersionName2'},
+            current: {
+              label: 'current-label',
+              path: 'current-path',
+            },
           },
         },
-        context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"Invalid docs option \\"versions\\": unknown versions (unknownVersionName1,unknownVersionName2) found. Available version names are: current"`,
-    );
-  });
-
-  it('readVersionsMetadata simple site with disableVersioning while single version should throw', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
-
-    await expect(
-      readVersionsMetadata({
-        options: {...defaultOptions, disableVersioning: true},
-        context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"Docs: using \\"disableVersioning: true\\" option on a non-versioned site does not make sense."`,
-    );
-  });
-
-  it('readVersionsMetadata simple site without including current version should throw', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
-
-    await expect(
-      readVersionsMetadata({
-        options: {...defaultOptions, includeCurrentVersion: false},
-        context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"It is not possible to use docs without any version. Please check the configuration of these options: \\"includeCurrentVersion: false\\", \\"disableVersioning: false\\"."`,
-    );
-  });
-});
-
-describe('versioned site, pluginId=default', () => {
-  async function loadSite() {
-    const versionedSiteDir = path.resolve(
-      path.join(__dirname, '__fixtures__', 'versioned-site'),
-    );
-    const defaultOptions: PluginOptions = {
-      id: DEFAULT_PLUGIN_ID,
-      ...DEFAULT_OPTIONS,
-      sidebarPath: 'sidebars.json',
-    };
-    const defaultContext = {
-      siteDir: versionedSiteDir,
-      baseUrl: '/',
-      i18n: DefaultI18N,
-    };
-
-    const vCurrent: VersionMetadata = {
-      contentPath: path.join(versionedSiteDir, 'docs'),
-      contentPathLocalized: path.join(
-        versionedSiteDir,
-        'i18n/en/docusaurus-plugin-content-docs/current',
-      ),
-      isLast: false,
-      routePriority: undefined,
-      sidebarFilePath: path.join(versionedSiteDir, 'sidebars.json'),
-      tagsPath: '/docs/next/tags',
-      versionLabel: 'Next',
-      versionName: 'current',
-      versionPath: '/docs/next',
-      versionBanner: 'unreleased',
-      versionBadge: true,
-      versionClassName: 'docs-version-current',
-    };
-
-    const v101: VersionMetadata = {
-      contentPath: path.join(versionedSiteDir, 'versioned_docs/version-1.0.1'),
-      contentPathLocalized: path.join(
-        versionedSiteDir,
-        'i18n/en/docusaurus-plugin-content-docs/version-1.0.1',
-      ),
-      isLast: true,
-      routePriority: -1,
-      sidebarFilePath: path.join(
-        versionedSiteDir,
-        'versioned_sidebars/version-1.0.1-sidebars.json',
-      ),
-      tagsPath: '/docs/tags',
-      versionLabel: '1.0.1',
-      versionName: '1.0.1',
-      versionPath: '/docs',
-      versionBanner: null,
-      versionBadge: true,
-      versionClassName: 'docs-version-1.0.1',
-    };
-
-    const v100: VersionMetadata = {
-      contentPath: path.join(versionedSiteDir, 'versioned_docs/version-1.0.0'),
-      contentPathLocalized: path.join(
-        versionedSiteDir,
-        'i18n/en/docusaurus-plugin-content-docs/version-1.0.0',
-      ),
-      isLast: false,
-      routePriority: undefined,
-      sidebarFilePath: path.join(
-        versionedSiteDir,
-        'versioned_sidebars/version-1.0.0-sidebars.json',
-      ),
-      tagsPath: '/docs/1.0.0/tags',
-      versionLabel: '1.0.0',
-      versionName: '1.0.0',
-      versionPath: '/docs/1.0.0',
-      versionBanner: 'unmaintained',
-      versionBadge: true,
-      versionClassName: 'docs-version-1.0.0',
-    };
-
-    const vWithSlugs: VersionMetadata = {
-      contentPath: path.join(
-        versionedSiteDir,
-        'versioned_docs/version-withSlugs',
-      ),
-      contentPathLocalized: path.join(
-        versionedSiteDir,
-        'i18n/en/docusaurus-plugin-content-docs/version-withSlugs',
-      ),
-      isLast: false,
-      routePriority: undefined,
-      sidebarFilePath: path.join(
-        versionedSiteDir,
-        'versioned_sidebars/version-withSlugs-sidebars.json',
-      ),
-      tagsPath: '/docs/withSlugs/tags',
-      versionLabel: 'withSlugs',
-      versionName: 'withSlugs',
-      versionPath: '/docs/withSlugs',
-      versionBanner: 'unmaintained',
-      versionBadge: true,
-      versionClassName: 'docs-version-withSlugs',
-    };
-
-    return {
-      versionedSiteDir,
-      defaultOptions,
-      defaultContext,
-      vCurrent,
-      v101,
-      v100,
-      vWithSlugs,
-    };
-  }
-
-  it('readVersionsMetadata versioned site', async () => {
-    const {defaultOptions, defaultContext, vCurrent, v101, v100, vWithSlugs} =
-      await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: defaultOptions,
-      context: defaultContext,
-    });
-
-    expect(versionsMetadata).toEqual([vCurrent, v101, v100, vWithSlugs]);
-  });
-
-  it('readVersionsMetadata versioned site with includeCurrentVersion=false', async () => {
-    const {defaultOptions, defaultContext, v101, v100, vWithSlugs} =
-      await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: {...defaultOptions, includeCurrentVersion: false},
-      context: defaultContext,
-    });
-
-    expect(versionsMetadata).toEqual([
-      // vCurrent removed
-      v101,
-      v100,
-      vWithSlugs,
-    ]);
-  });
-
-  it('readVersionsMetadata versioned site with version options', async () => {
-    const {defaultOptions, defaultContext, vCurrent, v101, v100, vWithSlugs} =
-      await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: {
-        ...defaultOptions,
-        lastVersion: '1.0.0',
-        versions: {
-          current: {
-            path: 'current-path',
-            banner: 'unmaintained',
-            badge: false,
-            className: 'custom-current-className',
-          },
-          '1.0.0': {
-            label: '1.0.0-label',
-            banner: 'unreleased',
-          },
+        context: {
+          ...defaultContext,
+          baseUrl: '/myBaseUrl',
         },
-      },
-      context: defaultContext,
+      });
+
+      expect(versionsMetadata).toEqual([
+        {
+          ...vCurrent,
+          versionPath: '/myBaseUrl/docs/current-path',
+          versionLabel: 'current-label',
+          routePriority: undefined,
+          sidebarFilePath: undefined,
+          tagsPath: '/myBaseUrl/docs/current-path/tags',
+          versionEditUrl: undefined,
+          versionEditUrlLocalized: undefined,
+        },
+      ]);
     });
 
-    expect(versionsMetadata).toEqual([
-      {
-        ...vCurrent,
-        tagsPath: '/docs/current-path/tags',
-        versionPath: '/docs/current-path',
-        versionBanner: 'unmaintained',
-        versionBadge: false,
-        versionClassName: 'custom-current-className',
-      },
-      {
-        ...v101,
+    it('throws with unknown lastVersion', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {...defaultOptions, lastVersion: 'unknownVersionName'},
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"Docs option lastVersion: unknownVersionName is invalid. Available version names are: current"`,
+      );
+    });
+
+    it('throws with unknown version configurations', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {
+            ...defaultOptions,
+            versions: {
+              current: {label: 'current'},
+              unknownVersionName1: {label: 'unknownVersionName1'},
+              unknownVersionName2: {label: 'unknownVersionName2'},
+            },
+          },
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"Invalid docs option \\"versions\\": unknown versions (unknownVersionName1,unknownVersionName2) found. Available version names are: current"`,
+      );
+    });
+
+    it('throws with disableVersioning while single version', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {...defaultOptions, disableVersioning: true},
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"Docs: using \\"disableVersioning: true\\" option on a non-versioned site does not make sense."`,
+      );
+    });
+
+    it('throws without including current version', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {...defaultOptions, includeCurrentVersion: false},
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"It is not possible to use docs without any version. Please check the configuration of these options: \\"includeCurrentVersion: false\\", \\"disableVersioning: false\\"."`,
+      );
+    });
+  });
+
+  describe('versioned site, pluginId=default', () => {
+    async function loadSite() {
+      const versionedSiteDir = path.resolve(
+        path.join(__dirname, '__fixtures__', 'versioned-site'),
+      );
+      const defaultOptions: PluginOptions = {
+        id: DEFAULT_PLUGIN_ID,
+        ...DEFAULT_OPTIONS,
+        sidebarPath: 'sidebars.json',
+      };
+      const defaultContext = {
+        siteDir: versionedSiteDir,
+        baseUrl: '/',
+        i18n: DefaultI18N,
+      };
+
+      const vCurrent: VersionMetadata = {
+        contentPath: path.join(versionedSiteDir, 'docs'),
+        contentPathLocalized: path.join(
+          versionedSiteDir,
+          'i18n/en/docusaurus-plugin-content-docs/current',
+        ),
         isLast: false,
         routePriority: undefined,
-        tagsPath: '/docs/1.0.1/tags',
-        versionPath: '/docs/1.0.1',
+        sidebarFilePath: path.join(versionedSiteDir, 'sidebars.json'),
+        tagsPath: '/docs/next/tags',
+        versionLabel: 'Next',
+        versionName: 'current',
+        versionPath: '/docs/next',
         versionBanner: 'unreleased',
-      },
-      {
-        ...v100,
-        isLast: true,
-        routePriority: -1,
-        tagsPath: '/docs/tags',
-        versionLabel: '1.0.0-label',
-        versionPath: '/docs',
-        versionBanner: 'unreleased',
-      },
-      vWithSlugs,
-    ]);
-  });
-
-  it('readVersionsMetadata versioned site with editUrl', async () => {
-    const {defaultOptions, defaultContext, vCurrent, v101, v100, vWithSlugs} =
-      await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: {
-        ...defaultOptions,
-        editUrl: 'https://github.com/facebook/docusaurus/edit/main/website/',
-      },
-      context: defaultContext,
-    });
-
-    expect(versionsMetadata).toEqual([
-      {
-        ...vCurrent,
-        versionEditUrl:
-          'https://github.com/facebook/docusaurus/edit/main/website/docs',
-        versionEditUrlLocalized:
-          'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
-      },
-      {
-        ...v101,
-        versionEditUrl:
-          'https://github.com/facebook/docusaurus/edit/main/website/versioned_docs/version-1.0.1',
-        versionEditUrlLocalized:
-          'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/version-1.0.1',
-      },
-      {
-        ...v100,
-        versionEditUrl:
-          'https://github.com/facebook/docusaurus/edit/main/website/versioned_docs/version-1.0.0',
-        versionEditUrlLocalized:
-          'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/version-1.0.0',
-      },
-      {
-        ...vWithSlugs,
-        versionEditUrl:
-          'https://github.com/facebook/docusaurus/edit/main/website/versioned_docs/version-withSlugs',
-        versionEditUrlLocalized:
-          'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/version-withSlugs',
-      },
-    ]);
-  });
-
-  it('readVersionsMetadata versioned site with editUrl and editCurrentVersion=true', async () => {
-    const {defaultOptions, defaultContext, vCurrent, v101, v100, vWithSlugs} =
-      await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: {
-        ...defaultOptions,
-        editUrl: 'https://github.com/facebook/docusaurus/edit/main/website/',
-        editCurrentVersion: true,
-      },
-      context: defaultContext,
-    });
-
-    expect(versionsMetadata).toEqual([
-      {
-        ...vCurrent,
-        versionEditUrl:
-          'https://github.com/facebook/docusaurus/edit/main/website/docs',
-        versionEditUrlLocalized:
-          'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
-      },
-      {
-        ...v101,
-        versionEditUrl:
-          'https://github.com/facebook/docusaurus/edit/main/website/docs',
-        versionEditUrlLocalized:
-          'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
-      },
-      {
-        ...v100,
-        versionEditUrl:
-          'https://github.com/facebook/docusaurus/edit/main/website/docs',
-        versionEditUrlLocalized:
-          'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
-      },
-      {
-        ...vWithSlugs,
-        versionEditUrl:
-          'https://github.com/facebook/docusaurus/edit/main/website/docs',
-        versionEditUrlLocalized:
-          'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
-      },
-    ]);
-  });
-
-  it('readVersionsMetadata versioned site with onlyIncludeVersions option', async () => {
-    const {defaultOptions, defaultContext, v101, vWithSlugs} = await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: {
-        ...defaultOptions,
-        // Order reversed on purpose: should not have any impact
-        onlyIncludeVersions: [vWithSlugs.versionName, v101.versionName],
-      },
-      context: defaultContext,
-    });
-
-    expect(versionsMetadata).toEqual([v101, vWithSlugs]);
-  });
-
-  it('readVersionsMetadata versioned site with disableVersioning', async () => {
-    const {defaultOptions, defaultContext, vCurrent} = await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: {...defaultOptions, disableVersioning: true},
-      context: defaultContext,
-    });
-
-    expect(versionsMetadata).toEqual([
-      {
-        ...vCurrent,
+        versionBadge: true,
+        versionClassName: 'docs-version-current',
+      };
+
+      const v101: VersionMetadata = {
+        contentPath: path.join(
+          versionedSiteDir,
+          'versioned_docs/version-1.0.1',
+        ),
+        contentPathLocalized: path.join(
+          versionedSiteDir,
+          'i18n/en/docusaurus-plugin-content-docs/version-1.0.1',
+        ),
         isLast: true,
         routePriority: -1,
+        sidebarFilePath: path.join(
+          versionedSiteDir,
+          'versioned_sidebars/version-1.0.1-sidebars.json',
+        ),
         tagsPath: '/docs/tags',
+        versionLabel: '1.0.1',
+        versionName: '1.0.1',
         versionPath: '/docs',
         versionBanner: null,
-        versionBadge: false,
-      },
-    ]);
-  });
+        versionBadge: true,
+        versionClassName: 'docs-version-1.0.1',
+      };
 
-  it('readVersionsMetadata versioned site with all versions disabled', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
+      const v100: VersionMetadata = {
+        contentPath: path.join(
+          versionedSiteDir,
+          'versioned_docs/version-1.0.0',
+        ),
+        contentPathLocalized: path.join(
+          versionedSiteDir,
+          'i18n/en/docusaurus-plugin-content-docs/version-1.0.0',
+        ),
+        isLast: false,
+        routePriority: undefined,
+        sidebarFilePath: path.join(
+          versionedSiteDir,
+          'versioned_sidebars/version-1.0.0-sidebars.json',
+        ),
+        tagsPath: '/docs/1.0.0/tags',
+        versionLabel: '1.0.0',
+        versionName: '1.0.0',
+        versionPath: '/docs/1.0.0',
+        versionBanner: 'unmaintained',
+        versionBadge: true,
+        versionClassName: 'docs-version-1.0.0',
+      };
 
-    await expect(
-      readVersionsMetadata({
-        options: {
-          ...defaultOptions,
-          includeCurrentVersion: false,
-          disableVersioning: true,
-        },
-        context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"It is not possible to use docs without any version. Please check the configuration of these options: \\"includeCurrentVersion: false\\", \\"disableVersioning: true\\"."`,
-    );
-  });
+      const vWithSlugs: VersionMetadata = {
+        contentPath: path.join(
+          versionedSiteDir,
+          'versioned_docs/version-withSlugs',
+        ),
+        contentPathLocalized: path.join(
+          versionedSiteDir,
+          'i18n/en/docusaurus-plugin-content-docs/version-withSlugs',
+        ),
+        isLast: false,
+        routePriority: undefined,
+        sidebarFilePath: path.join(
+          versionedSiteDir,
+          'versioned_sidebars/version-withSlugs-sidebars.json',
+        ),
+        tagsPath: '/docs/withSlugs/tags',
+        versionLabel: 'withSlugs',
+        versionName: 'withSlugs',
+        versionPath: '/docs/withSlugs',
+        versionBanner: 'unmaintained',
+        versionBadge: true,
+        versionClassName: 'docs-version-withSlugs',
+      };
 
-  it('readVersionsMetadata versioned site with empty onlyIncludeVersions', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
+      return {
+        versionedSiteDir,
+        defaultOptions,
+        defaultContext,
+        vCurrent,
+        v101,
+        v100,
+        vWithSlugs,
+      };
+    }
 
-    await expect(
-      readVersionsMetadata({
-        options: {
-          ...defaultOptions,
-          onlyIncludeVersions: [],
-        },
-        context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"Invalid docs option \\"onlyIncludeVersions\\": an empty array is not allowed, at least one version is needed."`,
-    );
-  });
+    it('works', async () => {
+      const {defaultOptions, defaultContext, vCurrent, v101, v100, vWithSlugs} =
+        await loadSite();
 
-  it('readVersionsMetadata versioned site with unknown versions in onlyIncludeVersions', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
-
-    await expect(
-      readVersionsMetadata({
-        options: {
-          ...defaultOptions,
-          onlyIncludeVersions: ['unknownVersion1', 'unknownVersion2'],
-        },
-        context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"Invalid docs option \\"onlyIncludeVersions\\": unknown versions (unknownVersion1,unknownVersion2) found. Available version names are: current, 1.0.1, 1.0.0, withSlugs"`,
-    );
-  });
-
-  it('readVersionsMetadata versioned site with lastVersion not in onlyIncludeVersions', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
-
-    await expect(
-      readVersionsMetadata({
-        options: {
-          ...defaultOptions,
-          lastVersion: '1.0.1',
-          onlyIncludeVersions: ['current', '1.0.0'],
-        },
-        context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"Invalid docs option \\"lastVersion\\": if you use both the \\"onlyIncludeVersions\\" and \\"lastVersion\\" options, then \\"lastVersion\\" must be present in the provided \\"onlyIncludeVersions\\" array."`,
-    );
-  });
-
-  it('readVersionsMetadata versioned site with invalid versions.json file', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
-
-    const mock = jest.spyOn(JSON, 'parse').mockImplementationOnce(() => ({
-      invalid: 'json',
-    }));
-
-    await expect(
-      readVersionsMetadata({
+      const versionsMetadata = await readVersionsMetadata({
         options: defaultOptions,
         context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"The versions file should contain an array of versions! Found content: {\\"invalid\\":\\"json\\"}"`,
-    );
-    mock.mockRestore();
-  });
-});
+      });
 
-describe('versioned site, pluginId=community', () => {
-  async function loadSite() {
-    const versionedSiteDir = path.resolve(
-      path.join(__dirname, '__fixtures__', 'versioned-site'),
-    );
-    const defaultOptions: PluginOptions = {
-      ...DEFAULT_OPTIONS,
-      id: 'community',
-      path: 'community',
-      routeBasePath: 'communityBasePath',
-      sidebarPath: 'sidebars.json',
-    };
-    const defaultContext = {
-      siteDir: versionedSiteDir,
-      baseUrl: '/',
-      i18n: DefaultI18N,
-    };
-
-    const vCurrent: VersionMetadata = {
-      contentPath: path.join(versionedSiteDir, 'community'),
-      contentPathLocalized: path.join(
-        versionedSiteDir,
-        'i18n/en/docusaurus-plugin-content-docs-community/current',
-      ),
-      isLast: false,
-      routePriority: undefined,
-      sidebarFilePath: path.join(versionedSiteDir, 'sidebars.json'),
-      tagsPath: '/communityBasePath/next/tags',
-      versionLabel: 'Next',
-      versionName: 'current',
-      versionPath: '/communityBasePath/next',
-      versionBanner: 'unreleased',
-      versionBadge: true,
-      versionClassName: 'docs-version-current',
-    };
-
-    const v100: VersionMetadata = {
-      contentPath: path.join(
-        versionedSiteDir,
-        'community_versioned_docs/version-1.0.0',
-      ),
-      contentPathLocalized: path.join(
-        versionedSiteDir,
-        'i18n/en/docusaurus-plugin-content-docs-community/version-1.0.0',
-      ),
-      isLast: true,
-      routePriority: -1,
-      sidebarFilePath: path.join(
-        versionedSiteDir,
-        'community_versioned_sidebars/version-1.0.0-sidebars.json',
-      ),
-      tagsPath: '/communityBasePath/tags',
-      versionLabel: '1.0.0',
-      versionName: '1.0.0',
-      versionPath: '/communityBasePath',
-      versionBanner: null,
-      versionBadge: true,
-      versionClassName: 'docs-version-1.0.0',
-    };
-
-    return {versionedSiteDir, defaultOptions, defaultContext, vCurrent, v100};
-  }
-
-  it('readVersionsMetadata versioned site (community)', async () => {
-    const {defaultOptions, defaultContext, vCurrent, v100} = await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: defaultOptions,
-      context: defaultContext,
+      expect(versionsMetadata).toEqual([vCurrent, v101, v100, vWithSlugs]);
     });
 
-    expect(versionsMetadata).toEqual([vCurrent, v100]);
-  });
+    it('works with includeCurrentVersion=false', async () => {
+      const {defaultOptions, defaultContext, v101, v100, vWithSlugs} =
+        await loadSite();
 
-  it('readVersionsMetadata versioned site (community) with includeCurrentVersion=false', async () => {
-    const {defaultOptions, defaultContext, v100} = await loadSite();
+      const versionsMetadata = await readVersionsMetadata({
+        options: {...defaultOptions, includeCurrentVersion: false},
+        context: defaultContext,
+      });
 
-    const versionsMetadata = await readVersionsMetadata({
-      options: {...defaultOptions, includeCurrentVersion: false},
-      context: defaultContext,
+      expect(versionsMetadata).toEqual([
+        // vCurrent removed
+        v101,
+        v100,
+        vWithSlugs,
+      ]);
     });
 
-    expect(versionsMetadata).toEqual([
-      // vCurrent removed
-      {...v100, versionBadge: false},
-    ]);
-  });
+    it('works with version options', async () => {
+      const {defaultOptions, defaultContext, vCurrent, v101, v100, vWithSlugs} =
+        await loadSite();
 
-  it('readVersionsMetadata versioned site (community) with disableVersioning', async () => {
-    const {defaultOptions, defaultContext, vCurrent} = await loadSite();
-
-    const versionsMetadata = await readVersionsMetadata({
-      options: {...defaultOptions, disableVersioning: true},
-      context: defaultContext,
-    });
-
-    expect(versionsMetadata).toEqual([
-      {
-        ...vCurrent,
-        isLast: true,
-        routePriority: -1,
-        tagsPath: '/communityBasePath/tags',
-        versionPath: '/communityBasePath',
-        versionBanner: null,
-        versionBadge: false,
-      },
-    ]);
-  });
-
-  it('readVersionsMetadata versioned site (community) with all versions disabled', async () => {
-    const {defaultOptions, defaultContext} = await loadSite();
-
-    await expect(
-      readVersionsMetadata({
+      const versionsMetadata = await readVersionsMetadata({
         options: {
           ...defaultOptions,
-          includeCurrentVersion: false,
-          disableVersioning: true,
+          lastVersion: '1.0.0',
+          versions: {
+            current: {
+              path: 'current-path',
+              banner: 'unmaintained',
+              badge: false,
+              className: 'custom-current-className',
+            },
+            '1.0.0': {
+              label: '1.0.0-label',
+              banner: 'unreleased',
+            },
+          },
         },
         context: defaultContext,
-      }),
-    ).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"It is not possible to use docs without any version. Please check the configuration of these options: \\"includeCurrentVersion: false\\", \\"disableVersioning: true\\"."`,
-    );
+      });
+
+      expect(versionsMetadata).toEqual([
+        {
+          ...vCurrent,
+          tagsPath: '/docs/current-path/tags',
+          versionPath: '/docs/current-path',
+          versionBanner: 'unmaintained',
+          versionBadge: false,
+          versionClassName: 'custom-current-className',
+        },
+        {
+          ...v101,
+          isLast: false,
+          routePriority: undefined,
+          tagsPath: '/docs/1.0.1/tags',
+          versionPath: '/docs/1.0.1',
+          versionBanner: 'unreleased',
+        },
+        {
+          ...v100,
+          isLast: true,
+          routePriority: -1,
+          tagsPath: '/docs/tags',
+          versionLabel: '1.0.0-label',
+          versionPath: '/docs',
+          versionBanner: 'unreleased',
+        },
+        vWithSlugs,
+      ]);
+    });
+
+    it('works with editUrl', async () => {
+      const {defaultOptions, defaultContext, vCurrent, v101, v100, vWithSlugs} =
+        await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
+        options: {
+          ...defaultOptions,
+          editUrl: 'https://github.com/facebook/docusaurus/edit/main/website/',
+        },
+        context: defaultContext,
+      });
+
+      expect(versionsMetadata).toEqual([
+        {
+          ...vCurrent,
+          versionEditUrl:
+            'https://github.com/facebook/docusaurus/edit/main/website/docs',
+          versionEditUrlLocalized:
+            'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
+        },
+        {
+          ...v101,
+          versionEditUrl:
+            'https://github.com/facebook/docusaurus/edit/main/website/versioned_docs/version-1.0.1',
+          versionEditUrlLocalized:
+            'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/version-1.0.1',
+        },
+        {
+          ...v100,
+          versionEditUrl:
+            'https://github.com/facebook/docusaurus/edit/main/website/versioned_docs/version-1.0.0',
+          versionEditUrlLocalized:
+            'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/version-1.0.0',
+        },
+        {
+          ...vWithSlugs,
+          versionEditUrl:
+            'https://github.com/facebook/docusaurus/edit/main/website/versioned_docs/version-withSlugs',
+          versionEditUrlLocalized:
+            'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/version-withSlugs',
+        },
+      ]);
+    });
+
+    it('works with editUrl and editCurrentVersion=true', async () => {
+      const {defaultOptions, defaultContext, vCurrent, v101, v100, vWithSlugs} =
+        await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
+        options: {
+          ...defaultOptions,
+          editUrl: 'https://github.com/facebook/docusaurus/edit/main/website/',
+          editCurrentVersion: true,
+        },
+        context: defaultContext,
+      });
+
+      expect(versionsMetadata).toEqual([
+        {
+          ...vCurrent,
+          versionEditUrl:
+            'https://github.com/facebook/docusaurus/edit/main/website/docs',
+          versionEditUrlLocalized:
+            'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
+        },
+        {
+          ...v101,
+          versionEditUrl:
+            'https://github.com/facebook/docusaurus/edit/main/website/docs',
+          versionEditUrlLocalized:
+            'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
+        },
+        {
+          ...v100,
+          versionEditUrl:
+            'https://github.com/facebook/docusaurus/edit/main/website/docs',
+          versionEditUrlLocalized:
+            'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
+        },
+        {
+          ...vWithSlugs,
+          versionEditUrl:
+            'https://github.com/facebook/docusaurus/edit/main/website/docs',
+          versionEditUrlLocalized:
+            'https://github.com/facebook/docusaurus/edit/main/website/i18n/en/docusaurus-plugin-content-docs/current',
+        },
+      ]);
+    });
+
+    it('works with onlyIncludeVersions option', async () => {
+      const {defaultOptions, defaultContext, v101, vWithSlugs} =
+        await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
+        options: {
+          ...defaultOptions,
+          // Order reversed on purpose: should not have any impact
+          onlyIncludeVersions: [vWithSlugs.versionName, v101.versionName],
+        },
+        context: defaultContext,
+      });
+
+      expect(versionsMetadata).toEqual([v101, vWithSlugs]);
+    });
+
+    it('works with disableVersioning', async () => {
+      const {defaultOptions, defaultContext, vCurrent} = await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
+        options: {...defaultOptions, disableVersioning: true},
+        context: defaultContext,
+      });
+
+      expect(versionsMetadata).toEqual([
+        {
+          ...vCurrent,
+          isLast: true,
+          routePriority: -1,
+          tagsPath: '/docs/tags',
+          versionPath: '/docs',
+          versionBanner: null,
+          versionBadge: false,
+        },
+      ]);
+    });
+
+    it('throws with all versions disabled', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {
+            ...defaultOptions,
+            includeCurrentVersion: false,
+            disableVersioning: true,
+          },
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"It is not possible to use docs without any version. Please check the configuration of these options: \\"includeCurrentVersion: false\\", \\"disableVersioning: true\\"."`,
+      );
+    });
+
+    it('throws with empty onlyIncludeVersions', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {
+            ...defaultOptions,
+            onlyIncludeVersions: [],
+          },
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"Invalid docs option \\"onlyIncludeVersions\\": an empty array is not allowed, at least one version is needed."`,
+      );
+    });
+
+    it('throws with unknown versions in onlyIncludeVersions', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {
+            ...defaultOptions,
+            onlyIncludeVersions: ['unknownVersion1', 'unknownVersion2'],
+          },
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"Invalid docs option \\"onlyIncludeVersions\\": unknown versions (unknownVersion1,unknownVersion2) found. Available version names are: current, 1.0.1, 1.0.0, withSlugs"`,
+      );
+    });
+
+    it('throws with lastVersion not in onlyIncludeVersions', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {
+            ...defaultOptions,
+            lastVersion: '1.0.1',
+            onlyIncludeVersions: ['current', '1.0.0'],
+          },
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"Invalid docs option \\"lastVersion\\": if you use both the \\"onlyIncludeVersions\\" and \\"lastVersion\\" options, then \\"lastVersion\\" must be present in the provided \\"onlyIncludeVersions\\" array."`,
+      );
+    });
+
+    it('throws with invalid versions.json file', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      const jsonMock = jest.spyOn(JSON, 'parse');
+      jsonMock.mockImplementationOnce(() => ({
+        invalid: 'json',
+      }));
+
+      await expect(
+        readVersionsMetadata({
+          options: defaultOptions,
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"The versions file should contain an array of version names! Found content: {\\"invalid\\":\\"json\\"}"`,
+      );
+      jsonMock.mockImplementationOnce(() => [1.1]);
+
+      await expect(
+        readVersionsMetadata({
+          options: defaultOptions,
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"Versions should be strings. Found type \\"number\\" for version \\"1.1\\"."`,
+      );
+      jsonMock.mockImplementationOnce(() => ['   ']);
+
+      await expect(
+        readVersionsMetadata({
+          options: defaultOptions,
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"Invalid version \\"   \\"."`,
+      );
+      jsonMock.mockRestore();
+    });
+  });
+
+  describe('versioned site, pluginId=community', () => {
+    async function loadSite() {
+      const versionedSiteDir = path.resolve(
+        path.join(__dirname, '__fixtures__', 'versioned-site'),
+      );
+      const defaultOptions: PluginOptions = {
+        ...DEFAULT_OPTIONS,
+        id: 'community',
+        path: 'community',
+        routeBasePath: 'communityBasePath',
+        sidebarPath: 'sidebars.json',
+      };
+      const defaultContext = {
+        siteDir: versionedSiteDir,
+        baseUrl: '/',
+        i18n: DefaultI18N,
+      };
+
+      const vCurrent: VersionMetadata = {
+        contentPath: path.join(versionedSiteDir, 'community'),
+        contentPathLocalized: path.join(
+          versionedSiteDir,
+          'i18n/en/docusaurus-plugin-content-docs-community/current',
+        ),
+        isLast: false,
+        routePriority: undefined,
+        sidebarFilePath: path.join(versionedSiteDir, 'sidebars.json'),
+        tagsPath: '/communityBasePath/next/tags',
+        versionLabel: 'Next',
+        versionName: 'current',
+        versionPath: '/communityBasePath/next',
+        versionBanner: 'unreleased',
+        versionBadge: true,
+        versionClassName: 'docs-version-current',
+      };
+
+      const v100: VersionMetadata = {
+        contentPath: path.join(
+          versionedSiteDir,
+          'community_versioned_docs/version-1.0.0',
+        ),
+        contentPathLocalized: path.join(
+          versionedSiteDir,
+          'i18n/en/docusaurus-plugin-content-docs-community/version-1.0.0',
+        ),
+        isLast: true,
+        routePriority: -1,
+        sidebarFilePath: path.join(
+          versionedSiteDir,
+          'community_versioned_sidebars/version-1.0.0-sidebars.json',
+        ),
+        tagsPath: '/communityBasePath/tags',
+        versionLabel: '1.0.0',
+        versionName: '1.0.0',
+        versionPath: '/communityBasePath',
+        versionBanner: null,
+        versionBadge: true,
+        versionClassName: 'docs-version-1.0.0',
+      };
+
+      return {versionedSiteDir, defaultOptions, defaultContext, vCurrent, v100};
+    }
+
+    it('works', async () => {
+      const {defaultOptions, defaultContext, vCurrent, v100} = await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
+        options: defaultOptions,
+        context: defaultContext,
+      });
+
+      expect(versionsMetadata).toEqual([vCurrent, v100]);
+    });
+
+    it('works with includeCurrentVersion=false', async () => {
+      const {defaultOptions, defaultContext, v100} = await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
+        options: {...defaultOptions, includeCurrentVersion: false},
+        context: defaultContext,
+      });
+
+      expect(versionsMetadata).toEqual([
+        // vCurrent removed
+        {...v100, versionBadge: false},
+      ]);
+    });
+
+    it('works with disableVersioning', async () => {
+      const {defaultOptions, defaultContext, vCurrent} = await loadSite();
+
+      const versionsMetadata = await readVersionsMetadata({
+        options: {...defaultOptions, disableVersioning: true},
+        context: defaultContext,
+      });
+
+      expect(versionsMetadata).toEqual([
+        {
+          ...vCurrent,
+          isLast: true,
+          routePriority: -1,
+          tagsPath: '/communityBasePath/tags',
+          versionPath: '/communityBasePath',
+          versionBanner: null,
+          versionBadge: false,
+        },
+      ]);
+    });
+
+    it('throws with all versions disabled', async () => {
+      const {defaultOptions, defaultContext} = await loadSite();
+
+      await expect(
+        readVersionsMetadata({
+          options: {
+            ...defaultOptions,
+            includeCurrentVersion: false,
+            disableVersioning: true,
+          },
+          context: defaultContext,
+        }),
+      ).rejects.toThrowErrorMatchingInlineSnapshot(
+        `"It is not possible to use docs without any version. Please check the configuration of these options: \\"includeCurrentVersion: false\\", \\"disableVersioning: true\\"."`,
+      );
+    });
   });
 });
diff --git a/packages/docusaurus-plugin-content-docs/src/docFrontMatter.ts b/packages/docusaurus-plugin-content-docs/src/docFrontMatter.ts
index 72e085b070..da4b86ca37 100644
--- a/packages/docusaurus-plugin-content-docs/src/docFrontMatter.ts
+++ b/packages/docusaurus-plugin-content-docs/src/docFrontMatter.ts
@@ -25,7 +25,7 @@ const DocFrontMatterSchema = Joi.object<DocFrontMatter>({
   hide_table_of_contents: Joi.boolean(),
   keywords: Joi.array().items(Joi.string().required()),
   image: URISchema,
-  description: Joi.string().allow(''), // see  https://github.com/facebook/docusaurus/issues/4591#issuecomment-822372398
+  description: Joi.string().allow(''), // see https://github.com/facebook/docusaurus/issues/4591#issuecomment-822372398
   slug: Joi.string(),
   sidebar_label: Joi.string(),
   sidebar_position: Joi.number(),
diff --git a/packages/docusaurus-plugin-content-docs/src/docs.ts b/packages/docusaurus-plugin-content-docs/src/docs.ts
index b58c4c2353..9fcfa8ee32 100644
--- a/packages/docusaurus-plugin-content-docs/src/docs.ts
+++ b/packages/docusaurus-plugin-content-docs/src/docs.ts
@@ -391,6 +391,10 @@ export const isCategoryIndex: CategoryIndexMatcher = ({
   return eligibleDocIndexNames.includes(fileName.toLowerCase());
 };
 
+/**
+ * `guides/sidebar/autogenerated.md` ->
+ *   `'autogenerated', '.md', ['sidebar', 'guides']`
+ */
 export function toCategoryIndexMatcherParam({
   source,
   sourceDirName,
@@ -406,28 +410,6 @@ export function toCategoryIndexMatcherParam({
   };
 }
 
-/**
- * `guides/sidebar/autogenerated.md` ->
- *   `'autogenerated', '.md', ['sidebar', 'guides']`
- */
-export function splitPath(str: string): {
-  /**
-   * The list of directories, from lowest level to highest.
-   * If there's no dir name, directories is ['.']
-   */
-  directories: string[];
-  /** The file name, without extension */
-  fileName: string;
-  /** The extension, with a leading dot */
-  extension: string;
-} {
-  return {
-    fileName: path.parse(str).name,
-    extension: path.parse(str).ext,
-    directories: path.dirname(str).split(path.sep).reverse(),
-  };
-}
-
 // Return both doc ids
 // TODO legacy retro-compatibility due to old versioned sidebars using
 // versioned doc ids ("id" should be removed & "versionedId" should be renamed
diff --git a/packages/docusaurus-plugin-content-docs/src/globalData.ts b/packages/docusaurus-plugin-content-docs/src/globalData.ts
index 9939fb7fca..bc974d527c 100644
--- a/packages/docusaurus-plugin-content-docs/src/globalData.ts
+++ b/packages/docusaurus-plugin-content-docs/src/globalData.ts
@@ -6,7 +6,6 @@
  */
 
 import _ from 'lodash';
-import {normalizeUrl} from '@docusaurus/utils';
 import type {Sidebars} from './sidebars/types';
 import {createSidebarsUtils} from './sidebars/utils';
 import type {
@@ -20,7 +19,7 @@ import type {
   GlobalDoc,
 } from '@docusaurus/plugin-content-docs/client';
 
-export function toGlobalDataDoc(doc: DocMetadata): GlobalDoc {
+function toGlobalDataDoc(doc: DocMetadata): GlobalDoc {
   return {
     id: doc.unversionedId,
     path: doc.permalink,
@@ -28,7 +27,7 @@ export function toGlobalDataDoc(doc: DocMetadata): GlobalDoc {
   };
 }
 
-export function toGlobalDataGeneratedIndex(
+function toGlobalDataGeneratedIndex(
   doc: CategoryGeneratedIndexMetadata,
 ): GlobalDoc {
   return {
@@ -38,7 +37,7 @@ export function toGlobalDataGeneratedIndex(
   };
 }
 
-export function toGlobalSidebars(
+function toGlobalSidebars(
   sidebars: Sidebars,
   version: LoadedVersion,
 ): Record<string, GlobalSidebar> {
@@ -52,7 +51,7 @@ export function toGlobalSidebars(
       link: {
         path:
           firstLink.type === 'generated-index'
-            ? normalizeUrl([version.versionPath, firstLink.slug])
+            ? firstLink.permalink
             : version.docs.find(
                 (doc) =>
                   doc.id === firstLink.id || doc.unversionedId === firstLink.id,
diff --git a/packages/docusaurus-plugin-content-docs/src/plugin-content-docs.d.ts b/packages/docusaurus-plugin-content-docs/src/plugin-content-docs.d.ts
index 95ec7b3635..f14be0f462 100644
--- a/packages/docusaurus-plugin-content-docs/src/plugin-content-docs.d.ts
+++ b/packages/docusaurus-plugin-content-docs/src/plugin-content-docs.d.ts
@@ -18,8 +18,14 @@ declare module '@docusaurus/plugin-content-docs' {
   };
 
   export type CategoryIndexMatcherParam = {
+    /** The file name, without extension */
     fileName: string;
+    /**
+     * The list of directories, from lowest level to highest.
+     * If there's no dir name, directories is ['.']
+     */
     directories: string[];
+    /** The extension, with a leading dot */
     extension: string;
   };
   export type CategoryIndexMatcher = (
diff --git a/packages/docusaurus-plugin-content-docs/src/sidebars/__tests__/utils.test.ts b/packages/docusaurus-plugin-content-docs/src/sidebars/__tests__/utils.test.ts
index c6a740fb84..1b75e8e65e 100644
--- a/packages/docusaurus-plugin-content-docs/src/sidebars/__tests__/utils.test.ts
+++ b/packages/docusaurus-plugin-content-docs/src/sidebars/__tests__/utils.test.ts
@@ -111,7 +111,7 @@ describe('createSidebarsUtils', () => {
       link: {
         type: 'generated-index',
         slug: '/s4-category-slug',
-        permalink: '/s4-category-permalink',
+        permalink: '/s4-category-slug',
       },
       items: [
         {type: 'doc', id: 'doc8'},
@@ -291,7 +291,7 @@ describe('createSidebarsUtils', () => {
     });
     expect(getFirstLink('sidebar4')).toEqual({
       type: 'generated-index',
-      slug: '/s4-category-slug',
+      permalink: '/s4-category-slug',
       label: 'S4 Category',
     });
   });
diff --git a/packages/docusaurus-plugin-content-docs/src/sidebars/utils.ts b/packages/docusaurus-plugin-content-docs/src/sidebars/utils.ts
index 20013e5208..da095918d5 100644
--- a/packages/docusaurus-plugin-content-docs/src/sidebars/utils.ts
+++ b/packages/docusaurus-plugin-content-docs/src/sidebars/utils.ts
@@ -139,6 +139,11 @@ export type SidebarsUtils = {
   getCategoryGeneratedIndexNavigation: (
     categoryGeneratedIndexPermalink: string,
   ) => SidebarNavigation;
+  /**
+   * This function may return undefined. This is usually a user mistake, because
+   * it means this sidebar will never be displayed; however, we can still use
+   * `displayed_sidebar` to make it displayed. Pretty weird but valid use-case
+   */
   getFirstLink: (sidebarId: string) =>
     | {
         type: 'doc';
@@ -147,7 +152,7 @@ export type SidebarsUtils = {
       }
     | {
         type: 'generated-index';
-        slug: string;
+        permalink: string;
         label: string;
       }
     | undefined;
@@ -295,7 +300,7 @@ Available document ids are:
       }
     | {
         type: 'generated-index';
-        slug: string;
+        permalink: string;
         label: string;
       }
     | undefined {
@@ -316,7 +321,7 @@ Available document ids are:
         } else if (item.link?.type === 'generated-index') {
           return {
             type: 'generated-index',
-            slug: item.link.slug,
+            permalink: item.link.permalink,
             label: item.label,
           };
         }
diff --git a/packages/docusaurus-plugin-content-docs/src/slug.ts b/packages/docusaurus-plugin-content-docs/src/slug.ts
index 14c99925dc..9de48aa13f 100644
--- a/packages/docusaurus-plugin-content-docs/src/slug.ts
+++ b/packages/docusaurus-plugin-content-docs/src/slug.ts
@@ -63,12 +63,11 @@ export default function getSlug({
   function ensureValidSlug(slug: string): string {
     if (!isValidPathname(slug)) {
       throw new Error(
-        `We couldn't compute a valid slug for document with id "${baseID}" in "${sourceDirName}" directory.
+        `We couldn't compute a valid slug for document with ID "${baseID}" in "${sourceDirName}" directory.
 The slug we computed looks invalid: ${slug}.
-Maybe your slug front matter is incorrect or you use weird chars in the file path?
-By using the slug front matter, you should be able to fix this error, by using the slug of your choice:
+Maybe your slug front matter is incorrect or there are special characters in the file path?
+By using front matter to set a custom slug, you should be able to fix this error:
 
-Example =>
 ---
 slug: /my/customDocPath
 ---
diff --git a/packages/docusaurus-plugin-content-docs/src/translations.ts b/packages/docusaurus-plugin-content-docs/src/translations.ts
index 49681b01ea..c6929f795e 100644
--- a/packages/docusaurus-plugin-content-docs/src/translations.ts
+++ b/packages/docusaurus-plugin-content-docs/src/translations.ts
@@ -274,10 +274,7 @@ function translateVersion(
   translationFiles: Record<string, TranslationFile>,
 ): LoadedVersion {
   const versionTranslations =
-    translationFiles[getVersionFileName(version.versionName)]?.content;
-  if (!versionTranslations) {
-    return version;
-  }
+    translationFiles[getVersionFileName(version.versionName)]!.content;
   return {
     ...version,
     versionLabel:
diff --git a/packages/docusaurus-plugin-content-docs/src/versions.ts b/packages/docusaurus-plugin-content-docs/src/versions.ts
index 08dbb0a796..6641184981 100644
--- a/packages/docusaurus-plugin-content-docs/src/versions.ts
+++ b/packages/docusaurus-plugin-content-docs/src/versions.ts
@@ -74,9 +74,9 @@ function ensureValidVersionString(version: unknown): asserts version is string {
 function ensureValidVersionArray(
   versionArray: unknown,
 ): asserts versionArray is string[] {
-  if (!(versionArray instanceof Array)) {
+  if (!Array.isArray(versionArray)) {
     throw new Error(
-      `The versions file should contain an array of versions! Found content: ${JSON.stringify(
+      `The versions file should contain an array of version names! Found content: ${JSON.stringify(
         versionArray,
       )}`,
     );
diff --git a/packages/docusaurus-theme-common/src/utils/docsPreferredVersion/DocsPreferredVersionProvider.tsx b/packages/docusaurus-theme-common/src/utils/docsPreferredVersion/DocsPreferredVersionProvider.tsx
index 49c74aa7b0..e425d86d53 100644
--- a/packages/docusaurus-theme-common/src/utils/docsPreferredVersion/DocsPreferredVersionProvider.tsx
+++ b/packages/docusaurus-theme-common/src/utils/docsPreferredVersion/DocsPreferredVersionProvider.tsx
@@ -92,13 +92,13 @@ function useVersionPersistence(): DocsVersionPersistence {
   return useThemeConfig().docs.versionPersistence;
 }
 
-// Value that  will be accessible through context: [state,api]
+// Value that will be accessible through context: [state,api]
 function useContextValue() {
   const allDocsData = useAllDocsData();
   const versionPersistence = useVersionPersistence();
   const pluginIds = useMemo(() => Object.keys(allDocsData), [allDocsData]);
 
-  // Initial state is empty, as  we can't read browser storage in node/SSR
+  // Initial state is empty, as we can't read browser storage in node/SSR
   const [state, setState] = useState(() => getInitialState(pluginIds));
 
   // On mount, we set the state read from browser storage
diff --git a/packages/docusaurus-theme-search-algolia/src/theme/SearchPage/index.tsx b/packages/docusaurus-theme-search-algolia/src/theme/SearchPage/index.tsx
index 61daf2266c..a9227bdff4 100644
--- a/packages/docusaurus-theme-search-algolia/src/theme/SearchPage/index.tsx
+++ b/packages/docusaurus-theme-search-algolia/src/theme/SearchPage/index.tsx
@@ -218,7 +218,7 @@ export default function SearchPage(): JSX.Element {
   algoliaHelper.on(
     'result',
     ({results: {query, hits, page, nbHits, nbPages}}) => {
-      if (query === '' || !(hits instanceof Array)) {
+      if (query === '' || !Array.isArray(hits)) {
         searchResultStateDispatcher({type: 'reset'});
         return;
       }
diff --git a/packages/docusaurus-utils/src/__tests__/markdownParser.test.ts b/packages/docusaurus-utils/src/__tests__/markdownParser.test.ts
index bc565f7550..01999c82c7 100644
--- a/packages/docusaurus-utils/src/__tests__/markdownParser.test.ts
+++ b/packages/docusaurus-utils/src/__tests__/markdownParser.test.ts
@@ -250,7 +250,7 @@ Lorem Ipsum
     });
   });
 
-  it('parses markdown h1 title at the top  followed by h2 title', () => {
+  it('parses markdown h1 title at the top followed by h2 title', () => {
     const markdown = dedent`
 
           # Markdown Title
diff --git a/packages/docusaurus/src/client/__tests__/normalizeLocation.test.ts b/packages/docusaurus/src/client/__tests__/normalizeLocation.test.ts
index df6294b60c..9517a5b0f1 100644
--- a/packages/docusaurus/src/client/__tests__/normalizeLocation.test.ts
+++ b/packages/docusaurus/src/client/__tests__/normalizeLocation.test.ts
@@ -9,7 +9,15 @@ import {jest} from '@jest/globals';
 import normalizeLocation from '../normalizeLocation';
 
 describe('normalizeLocation', () => {
-  it('rewrite locations with index.html', () => {
+  it('rewrites locations with index.html', () => {
+    expect(
+      normalizeLocation({
+        pathname: '/index.html',
+      }),
+    ).toEqual({
+      pathname: '/',
+    });
+
     expect(
       normalizeLocation({
         pathname: '/docs/introduction/index.html',
@@ -35,7 +43,7 @@ describe('normalizeLocation', () => {
     });
   });
 
-  it('untouched pathnames', () => {
+  it('leaves pathnames untouched', () => {
     const replaceMock = jest.spyOn(String.prototype, 'replace');
 
     expect(
diff --git a/packages/docusaurus/src/client/exports/Interpolate.tsx b/packages/docusaurus/src/client/exports/Interpolate.tsx
index 8b894f7032..5b290d6054 100644
--- a/packages/docusaurus/src/client/exports/Interpolate.tsx
+++ b/packages/docusaurus/src/client/exports/Interpolate.tsx
@@ -89,12 +89,12 @@ export function interpolate<Str extends string, Value extends ReactNode>(
 export default function Interpolate<Str extends string>({
   children,
   values,
-}: InterpolateProps<Str>): ReactNode {
+}: InterpolateProps<Str>): JSX.Element {
   if (typeof children !== 'string') {
     console.warn('Illegal <Interpolate> children', children);
     throw new Error(
       'The Docusaurus <Interpolate> component only accept simple string values',
     );
   }
-  return interpolate(children, values);
+  return <>{interpolate(children, values)}</>;
 }
diff --git a/packages/docusaurus/src/client/exports/Translate.tsx b/packages/docusaurus/src/client/exports/Translate.tsx
index 8e9c0f8fcc..5cfbef7edb 100644
--- a/packages/docusaurus/src/client/exports/Translate.tsx
+++ b/packages/docusaurus/src/client/exports/Translate.tsx
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import type {ReactNode} from 'react';
+import React from 'react';
 import {interpolate, type InterpolateValues} from '@docusaurus/Interpolate';
 import type {TranslateParam, TranslateProps} from '@docusaurus/Translate';
 
@@ -46,7 +46,7 @@ export default function Translate<Str extends string>({
   children,
   id,
   values,
-}: TranslateProps<Str>): ReactNode {
+}: TranslateProps<Str>): JSX.Element {
   if (children && typeof children !== 'string') {
     console.warn('Illegal <Translate> children', children);
     throw new Error(
@@ -55,5 +55,5 @@ export default function Translate<Str extends string>({
   }
 
   const localizedMessage: string = getLocalizedMessage({message: children, id});
-  return interpolate(localizedMessage, values);
+  return <>{interpolate(localizedMessage, values)}</>;
 }
diff --git a/packages/docusaurus/src/client/exports/__tests__/BrowserOnly.test.tsx b/packages/docusaurus/src/client/exports/__tests__/BrowserOnly.test.tsx
index 0de095ad04..7ab1c09720 100644
--- a/packages/docusaurus/src/client/exports/__tests__/BrowserOnly.test.tsx
+++ b/packages/docusaurus/src/client/exports/__tests__/BrowserOnly.test.tsx
@@ -5,46 +5,55 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {jest} from '@jest/globals';
 import React from 'react';
 import renderer from 'react-test-renderer';
 import BrowserOnly from '../BrowserOnly';
+import {Context} from '../browserContext';
 
-jest.mock('@docusaurus/useIsBrowser', () => () => true);
-
-describe('BrowserOnly', () => {
+describe('<BrowserOnly>', () => {
   it('rejects react element children', () => {
     process.env.NODE_ENV = 'development';
-    expect(() => {
-      renderer.create(
-        <BrowserOnly>
-          {/* @ts-expect-error test */}
-          <span>{window.location.href}</span>
-        </BrowserOnly>,
-      );
-    }).toThrowErrorMatchingInlineSnapshot(`
+    expect(() =>
+      renderer
+        .create(
+          <Context.Provider value>
+            <BrowserOnly>
+              {/* @ts-expect-error test */}
+              <span>{window.location.href}</span>
+            </BrowserOnly>
+          </Context.Provider>,
+        )
+        .toJSON(),
+    ).toThrowErrorMatchingInlineSnapshot(`
       "Docusaurus error: The children of <BrowserOnly> must be a \\"render function\\", e.g. <BrowserOnly>{() => <span>{window.location.href}</span>}</BrowserOnly>.
       Current type: React element"
     `);
   });
+
   it('rejects string children', () => {
+    process.env.NODE_ENV = 'development';
     expect(() => {
       renderer.create(
-        // @ts-expect-error test
-        <BrowserOnly> </BrowserOnly>,
+        <Context.Provider value>
+          {/* @ts-expect-error test */}
+          <BrowserOnly> </BrowserOnly>
+        </Context.Provider>,
       );
     }).toThrowErrorMatchingInlineSnapshot(`
       "Docusaurus error: The children of <BrowserOnly> must be a \\"render function\\", e.g. <BrowserOnly>{() => <span>{window.location.href}</span>}</BrowserOnly>.
       Current type: string"
     `);
   });
+
   it('accepts valid children', () => {
     expect(
       renderer
         .create(
-          <BrowserOnly fallback={<span>Loading</span>}>
-            {() => <span>{window.location.href}</span>}
-          </BrowserOnly>,
+          <Context.Provider value>
+            <BrowserOnly fallback={<span>Loading</span>}>
+              {() => <span>{window.location.href}</span>}
+            </BrowserOnly>
+          </Context.Provider>,
         )
         .toJSON(),
     ).toMatchInlineSnapshot(`
@@ -53,4 +62,36 @@ describe('BrowserOnly', () => {
       </span>
     `);
   });
+
+  it('returns fallback when not in browser', () => {
+    expect(
+      renderer
+        .create(
+          <Context.Provider value={false}>
+            <BrowserOnly fallback={<span>Loading</span>}>
+              {() => <span>{window.location.href}</span>}
+            </BrowserOnly>
+          </Context.Provider>,
+        )
+        .toJSON(),
+    ).toMatchInlineSnapshot(`
+      <span>
+        Loading
+      </span>
+    `);
+  });
+
+  it('gracefully falls back', () => {
+    expect(
+      renderer
+        .create(
+          <Context.Provider value={false}>
+            <BrowserOnly>
+              {() => <span>{window.location.href}</span>}
+            </BrowserOnly>
+          </Context.Provider>,
+        )
+        .toJSON(),
+    ).toMatchInlineSnapshot(`null`);
+  });
 });
diff --git a/packages/docusaurus/src/client/exports/__tests__/Interpolate.test.tsx b/packages/docusaurus/src/client/exports/__tests__/Interpolate.test.tsx
index 7cd3155722..fdf1033103 100644
--- a/packages/docusaurus/src/client/exports/__tests__/Interpolate.test.tsx
+++ b/packages/docusaurus/src/client/exports/__tests__/Interpolate.test.tsx
@@ -6,9 +6,10 @@
  */
 
 import React from 'react';
-import {interpolate} from '../Interpolate';
+import renderer from 'react-test-renderer';
+import Interpolate, {interpolate} from '../Interpolate';
 
-describe('Interpolate', () => {
+describe('interpolate', () => {
   it('without placeholders', () => {
     const text = 'Hello how are you?';
     expect(interpolate(text)).toEqual(text);
@@ -86,3 +87,50 @@ describe('Interpolate', () => {
     expect(interpolate(text, values)).toMatchSnapshot();
   });
 });
+
+describe('<Interpolate>', () => {
+  it('without placeholders', () => {
+    const text = 'Hello how are you?';
+    expect(renderer.create(<Interpolate>{text}</Interpolate>).toJSON()).toEqual(
+      text,
+    );
+  });
+
+  it('placeholders with string values', () => {
+    const text = 'Hello {name} how are you {day}?';
+    const values = {name: 'Sébastien', day: 'today'};
+    expect(
+      renderer
+        .create(<Interpolate values={values}>{text}</Interpolate>)
+        .toJSON(),
+    ).toMatchInlineSnapshot(`"Hello Sébastien how are you today?"`);
+  });
+
+  it('acceptance test', () => {
+    const text = 'Hello {name} how are you {day}? Another {unprovidedValue}!';
+    const values = {
+      name: 'Sébastien',
+      day: <span>today</span>,
+      extraUselessValue1: <div>test</div>,
+      extraUselessValue2: 'hi',
+    };
+    expect(
+      renderer
+        .create(<Interpolate values={values}>{text}</Interpolate>)
+        .toJSON(),
+    ).toMatchSnapshot();
+  });
+
+  it('rejects when children is not string', () => {
+    expect(() =>
+      renderer.create(
+        <Interpolate>
+          {/* @ts-expect-error: for test */}
+          <span>aaa</span>
+        </Interpolate>,
+      ),
+    ).toThrowErrorMatchingInlineSnapshot(
+      `"The Docusaurus <Interpolate> component only accept simple string values"`,
+    );
+  });
+});
diff --git a/packages/docusaurus/src/client/exports/__tests__/Translate.test.tsx b/packages/docusaurus/src/client/exports/__tests__/Translate.test.tsx
index b1e8efb76a..28a8f90fe6 100644
--- a/packages/docusaurus/src/client/exports/__tests__/Translate.test.tsx
+++ b/packages/docusaurus/src/client/exports/__tests__/Translate.test.tsx
@@ -5,28 +5,75 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {translate} from '../Translate';
+import React from 'react';
+import renderer from 'react-test-renderer';
+import Translate, {translate} from '../Translate';
 
 describe('translate', () => {
-  it('accept id and use it as fallback', () => {
+  it('accepts id and uses it as fallback', () => {
     expect(translate({id: 'some-id'})).toBe('some-id');
   });
 
-  it('accept message and use it as fallback', () => {
+  it('accepts message and uses it as fallback', () => {
     expect(translate({message: 'some-message'})).toBe('some-message');
   });
 
-  it('accept id+message and use message as fallback', () => {
+  it('accepts id+message and uses message as fallback', () => {
     expect(translate({id: 'some-id', message: 'some-message'})).toBe(
       'some-message',
     );
   });
 
-  it('reject when no id or message', () => {
-    // TODO tests are not resolving type defs correctly
+  it('rejects when no id or message', () => {
+    // TODO tests are not resolving type defs correctly. We need to include test
+    // files in a tsconfig file
     // @ts-expect-error: TS should protect when both id/message are missing
     expect(() => translate({})).toThrowErrorMatchingInlineSnapshot(
       `"Docusaurus translation declarations must have at least a translation id or a default translation message"`,
     );
   });
 });
+
+describe('<Translate>', () => {
+  it('accepts id and uses it as fallback', () => {
+    expect(renderer.create(<Translate id="some-id" />).toJSON()).toBe(
+      'some-id',
+    );
+  });
+
+  it('accepts message and uses it as fallback', () => {
+    expect(renderer.create(<Translate>some-message</Translate>).toJSON()).toBe(
+      'some-message',
+    );
+  });
+
+  it('accepts id+message and uses message as fallback', () => {
+    expect(
+      renderer
+        .create(<Translate id="some-id">some-message</Translate>)
+        .toJSON(),
+    ).toBe('some-message');
+  });
+
+  it('rejects when no id or message', () => {
+    expect(() =>
+      // @ts-expect-error: TS should protect when both id/message are missing
+      renderer.create(<Translate />),
+    ).toThrowErrorMatchingInlineSnapshot(
+      `"Docusaurus translation declarations must have at least a translation id or a default translation message"`,
+    );
+  });
+
+  it('rejects when children is not a string', () => {
+    expect(() =>
+      renderer.create(
+        <Translate id="foo">
+          {/* @ts-expect-error: for test */}
+          <span>aaa</span>
+        </Translate>,
+      ),
+    ).toThrowErrorMatchingInlineSnapshot(
+      `"The Docusaurus <Translate> component only accept simple string values"`,
+    );
+  });
+});
diff --git a/packages/docusaurus/src/client/exports/__tests__/__snapshots__/Interpolate.test.tsx.snap b/packages/docusaurus/src/client/exports/__tests__/__snapshots__/Interpolate.test.tsx.snap
index a42c4388ab..09d0dcadd9 100644
--- a/packages/docusaurus/src/client/exports/__tests__/__snapshots__/Interpolate.test.tsx.snap
+++ b/packages/docusaurus/src/client/exports/__tests__/__snapshots__/Interpolate.test.tsx.snap
@@ -1,6 +1,18 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`Interpolate acceptance test 1`] = `
+exports[`<Interpolate> acceptance test 1`] = `
+Array [
+  "Hello ",
+  "Sébastien",
+  " how are you ",
+  <span>
+    today
+  </span>,
+  "? Another {unprovidedValue}!",
+]
+`;
+
+exports[`interpolate acceptance test 1`] = `
 Array [
   <React.Fragment>
     Hello 
@@ -18,7 +30,7 @@ Array [
 ]
 `;
 
-exports[`Interpolate placeholders with JSX values 1`] = `
+exports[`interpolate placeholders with JSX values 1`] = `
 Array [
   <React.Fragment>
     Hello 
@@ -38,7 +50,7 @@ Array [
 ]
 `;
 
-exports[`Interpolate placeholders with mixed vales 1`] = `
+exports[`interpolate placeholders with mixed vales 1`] = `
 Array [
   <React.Fragment>
     Hello 
diff --git a/packages/docusaurus/src/client/exports/__tests__/browserContext.test.tsx b/packages/docusaurus/src/client/exports/__tests__/browserContext.test.tsx
new file mode 100644
index 0000000000..2802f91532
--- /dev/null
+++ b/packages/docusaurus/src/client/exports/__tests__/browserContext.test.tsx
@@ -0,0 +1,30 @@
+/**
+ * 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.
+ *
+ * @jest-environment jsdom
+ */
+
+// Jest doesn't allow pragma below other comments. https://github.com/facebook/jest/issues/12573
+// eslint-disable-next-line header/header
+import React from 'react';
+import {renderHook} from '@testing-library/react-hooks/server';
+import {BrowserContextProvider} from '../browserContext';
+import useIsBrowser from '../useIsBrowser';
+
+describe('BrowserContextProvider', () => {
+  const {result, hydrate} = renderHook(() => useIsBrowser(), {
+    wrapper: ({children}) => (
+      <BrowserContextProvider>{children}</BrowserContextProvider>
+    ),
+  });
+  it('has value false on first render', () => {
+    expect(result.current).toBe(false);
+  });
+  it('has value true on hydration', () => {
+    hydrate();
+    expect(result.current).toBe(true);
+  });
+});
diff --git a/packages/docusaurus/src/client/exports/__tests__/docusaurusContext.test.tsx b/packages/docusaurus/src/client/exports/__tests__/docusaurusContext.test.tsx
new file mode 100644
index 0000000000..062591f3b4
--- /dev/null
+++ b/packages/docusaurus/src/client/exports/__tests__/docusaurusContext.test.tsx
@@ -0,0 +1,41 @@
+/**
+ * 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.
+ *
+ * @jest-environment jsdom
+ */
+
+// Jest doesn't allow pragma below other comments. https://github.com/facebook/jest/issues/12573
+// eslint-disable-next-line header/header
+import React from 'react';
+import {renderHook} from '@testing-library/react-hooks/server';
+import {DocusaurusContextProvider} from '../docusaurusContext';
+import useDocusaurusContext from '../useDocusaurusContext';
+
+// This test currently isn't quite useful because the @generated aliases point
+// to the empty modules. Maybe we can point that to fixtures in the future.
+describe('DocusaurusContextProvider', () => {
+  const {result, hydrate} = renderHook(() => useDocusaurusContext(), {
+    wrapper: ({children}) => (
+      <DocusaurusContextProvider>{children}</DocusaurusContextProvider>
+    ),
+  });
+  const value = result.current;
+  it('returns right value', () => {
+    expect(value).toMatchInlineSnapshot(`
+      Object {
+        "codeTranslations": Object {},
+        "globalData": Object {},
+        "i18n": Object {},
+        "siteConfig": Object {},
+        "siteMetadata": Object {},
+      }
+    `);
+  });
+  it('has reference-equal value on hydration', () => {
+    hydrate();
+    expect(result.current).toBe(value);
+  });
+});
diff --git a/packages/docusaurus/src/client/exports/__tests__/useGlobalData.test.tsx b/packages/docusaurus/src/client/exports/__tests__/useGlobalData.test.tsx
new file mode 100644
index 0000000000..670a7e3bcc
--- /dev/null
+++ b/packages/docusaurus/src/client/exports/__tests__/useGlobalData.test.tsx
@@ -0,0 +1,122 @@
+/**
+ * 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 {renderHook} from '@testing-library/react-hooks';
+import useGlobalData, {
+  useAllPluginInstancesData,
+  usePluginData,
+} from '../useGlobalData';
+import {Context} from '../docusaurusContext';
+
+describe('useGlobalData', () => {
+  it('returns global data from context', () => {
+    expect(
+      renderHook(() => useGlobalData(), {
+        wrapper: ({children}) => (
+          // eslint-disable-next-line react/jsx-no-constructed-context-values
+          <Context.Provider value={{globalData: {foo: 'bar'}}}>
+            {children}
+          </Context.Provider>
+        ),
+      }).result.current,
+    ).toEqual({foo: 'bar'});
+  });
+
+  it('throws when global data not found', () => {
+    // Can it actually happen?
+    expect(
+      () =>
+        renderHook(() => useGlobalData(), {
+          wrapper: ({children}) => (
+            // eslint-disable-next-line react/jsx-no-constructed-context-values
+            <Context.Provider value={{}}>{children}</Context.Provider>
+          ),
+        }).result.current,
+    ).toThrowErrorMatchingInlineSnapshot(`"Docusaurus global data not found."`);
+  });
+});
+
+describe('useAllPluginInstancesData', () => {
+  it('returns plugin data namespace', () => {
+    expect(
+      renderHook(() => useAllPluginInstancesData('foo'), {
+        wrapper: ({children}) => (
+          <Context.Provider
+            // eslint-disable-next-line react/jsx-no-constructed-context-values
+            value={{globalData: {foo: {default: 'default', bar: 'bar'}}}}>
+            {children}
+          </Context.Provider>
+        ),
+      }).result.current,
+    ).toEqual({default: 'default', bar: 'bar'});
+  });
+
+  it('throws when plugin data not found', () => {
+    expect(
+      () =>
+        renderHook(() => useAllPluginInstancesData('bar'), {
+          wrapper: ({children}) => (
+            <Context.Provider
+              // eslint-disable-next-line react/jsx-no-constructed-context-values
+              value={{globalData: {foo: {default: 'default', bar: 'bar'}}}}>
+              {children}
+            </Context.Provider>
+          ),
+        }).result.current,
+    ).toThrowErrorMatchingInlineSnapshot(
+      `"Docusaurus plugin global data not found for \\"bar\\" plugin."`,
+    );
+  });
+});
+
+describe('usePluginData', () => {
+  it('returns plugin instance data', () => {
+    expect(
+      renderHook(() => usePluginData('foo', 'bar'), {
+        wrapper: ({children}) => (
+          <Context.Provider
+            // eslint-disable-next-line react/jsx-no-constructed-context-values
+            value={{globalData: {foo: {default: 'default', bar: 'bar'}}}}>
+            {children}
+          </Context.Provider>
+        ),
+      }).result.current,
+    ).toBe('bar');
+  });
+
+  it('defaults to default ID', () => {
+    expect(
+      renderHook(() => usePluginData('foo'), {
+        wrapper: ({children}) => (
+          <Context.Provider
+            // eslint-disable-next-line react/jsx-no-constructed-context-values
+            value={{globalData: {foo: {default: 'default', bar: 'bar'}}}}>
+            {children}
+          </Context.Provider>
+        ),
+      }).result.current,
+    ).toBe('default');
+  });
+
+  it('throws when plugin instance data not found', () => {
+    expect(
+      () =>
+        renderHook(() => usePluginData('foo', 'baz'), {
+          wrapper: ({children}) => (
+            <Context.Provider
+              // eslint-disable-next-line react/jsx-no-constructed-context-values
+              value={{globalData: {foo: {default: 'default', bar: 'bar'}}}}>
+              {children}
+            </Context.Provider>
+          ),
+        }).result.current,
+    ).toThrowErrorMatchingInlineSnapshot(
+      `"Docusaurus plugin global data not found for \\"foo\\" plugin with id \\"baz\\"."`,
+    );
+  });
+});
diff --git a/packages/docusaurus/src/client/normalizeLocation.ts b/packages/docusaurus/src/client/normalizeLocation.ts
index 18b408c33b..6d443c316e 100644
--- a/packages/docusaurus/src/client/normalizeLocation.ts
+++ b/packages/docusaurus/src/client/normalizeLocation.ts
@@ -18,12 +18,8 @@ export default function normalizeLocation<T extends Location>(location: T): T {
     };
   }
 
-  let pathname = location.pathname || '/';
-  pathname = pathname.trim().replace(/\/index\.html$/, '');
-
-  if (pathname === '') {
-    pathname = '/';
-  }
+  const pathname =
+    location.pathname.trim().replace(/\/index\.html$/, '') || '/';
 
   pathnames[location.pathname] = pathname;
 
diff --git a/packages/docusaurus/src/server/config.ts b/packages/docusaurus/src/server/config.ts
index 5f6d0ef01f..94e8656acf 100644
--- a/packages/docusaurus/src/server/config.ts
+++ b/packages/docusaurus/src/server/config.ts
@@ -24,7 +24,7 @@ export default async function loadConfig(
     | (() => Promise<Partial<DocusaurusConfig>>);
 
   const loadedConfig =
-    importedConfig instanceof Function
+    typeof importedConfig === 'function'
       ? await importedConfig()
       : await importedConfig;
 
diff --git a/packages/docusaurus/src/server/index.ts b/packages/docusaurus/src/server/index.ts
index 414125b416..d603c46c2d 100644
--- a/packages/docusaurus/src/server/index.ts
+++ b/packages/docusaurus/src/server/index.ts
@@ -464,7 +464,7 @@ ${Object.entries(registry)
   return props;
 }
 
-// We want all @docusaurus/* packages  to have the exact same version!
+// We want all @docusaurus/* packages to have the exact same version!
 // See https://github.com/facebook/docusaurus/issues/3371
 // See https://github.com/facebook/docusaurus/pull/3386
 function checkDocusaurusPackagesVersion(siteMetadata: DocusaurusSiteMetadata) {
diff --git a/packages/docusaurus/src/webpack/__tests__/__fixtures__/host.crt b/packages/docusaurus/src/webpack/__tests__/__fixtures__/host.crt
new file mode 100644
index 0000000000..81a7dc73bb
--- /dev/null
+++ b/packages/docusaurus/src/webpack/__tests__/__fixtures__/host.crt
@@ -0,0 +1,24 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/packages/docusaurus/src/webpack/__tests__/__fixtures__/host.key b/packages/docusaurus/src/webpack/__tests__/__fixtures__/host.key
new file mode 100644
index 0000000000..1b47cc35e4
--- /dev/null
+++ b/packages/docusaurus/src/webpack/__tests__/__fixtures__/host.key
@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
diff --git a/packages/docusaurus/src/webpack/__tests__/__fixtures__/invalid.crt b/packages/docusaurus/src/webpack/__tests__/__fixtures__/invalid.crt
new file mode 100644
index 0000000000..bc56c4d894
--- /dev/null
+++ b/packages/docusaurus/src/webpack/__tests__/__fixtures__/invalid.crt
@@ -0,0 +1 @@
+Foo
diff --git a/packages/docusaurus/src/webpack/__tests__/__fixtures__/invalid.key b/packages/docusaurus/src/webpack/__tests__/__fixtures__/invalid.key
new file mode 100644
index 0000000000..bc56c4d894
--- /dev/null
+++ b/packages/docusaurus/src/webpack/__tests__/__fixtures__/invalid.key
@@ -0,0 +1 @@
+Foo
diff --git a/packages/docusaurus/src/webpack/__tests__/server.test.ts b/packages/docusaurus/src/webpack/__tests__/server.test.ts
index fd4254258f..b722f46f7d 100644
--- a/packages/docusaurus/src/webpack/__tests__/server.test.ts
+++ b/packages/docusaurus/src/webpack/__tests__/server.test.ts
@@ -13,7 +13,7 @@ import loadSetup from '../../server/__tests__/testUtils';
 
 describe('webpack production config', () => {
   it('simple', async () => {
-    jest.spyOn(console, 'log').mockImplementation();
+    jest.spyOn(console, 'log').mockImplementation(() => {});
     const props = await loadSetup('simple');
     const config = await createServerConfig({props});
     const errors = webpack.validate(config);
@@ -21,7 +21,7 @@ describe('webpack production config', () => {
   });
 
   it('custom', async () => {
-    jest.spyOn(console, 'log').mockImplementation();
+    jest.spyOn(console, 'log').mockImplementation(() => {});
     const props = await loadSetup('custom');
     const config = await createServerConfig({props});
     const errors = webpack.validate(config);
diff --git a/packages/docusaurus/src/webpack/__tests__/utils.test.ts b/packages/docusaurus/src/webpack/__tests__/utils.test.ts
index 2b29331dbd..3b58b57d22 100644
--- a/packages/docusaurus/src/webpack/__tests__/utils.test.ts
+++ b/packages/docusaurus/src/webpack/__tests__/utils.test.ts
@@ -12,6 +12,7 @@ import {
   getCustomizableJSLoader,
   applyConfigureWebpack,
   applyConfigurePostCss,
+  getHttpsConfig,
 } from '../utils';
 import type {
   ConfigureWebpackFn,
@@ -297,3 +298,65 @@ describe('extending PostCSS', () => {
     ]);
   });
 });
+
+describe('getHttpsConfig', () => {
+  const originalEnv = process.env;
+
+  beforeEach(() => {
+    jest.resetModules();
+    process.env = {...originalEnv};
+  });
+
+  afterAll(() => {
+    process.env = originalEnv;
+  });
+
+  it('returns true for HTTPS not env', async () => {
+    await expect(getHttpsConfig()).resolves.toBe(false);
+  });
+
+  it('returns true for HTTPS in env', async () => {
+    process.env.HTTPS = 'true';
+    await expect(getHttpsConfig()).resolves.toBe(true);
+  });
+
+  it('returns custom certs if they are in env', async () => {
+    process.env.HTTPS = 'true';
+    process.env.SSL_CRT_FILE = path.join(__dirname, '__fixtures__/host.crt');
+    process.env.SSL_KEY_FILE = path.join(__dirname, '__fixtures__/host.key');
+    await expect(getHttpsConfig()).resolves.toEqual({
+      key: expect.any(Buffer),
+      cert: expect.any(Buffer),
+    });
+  });
+
+  it("throws if file doesn't exist", async () => {
+    process.env.HTTPS = 'true';
+    process.env.SSL_CRT_FILE = path.join(
+      __dirname,
+      '__fixtures__/nonexistent.crt',
+    );
+    process.env.SSL_KEY_FILE = path.join(__dirname, '__fixtures__/host.key');
+    await expect(getHttpsConfig()).rejects.toThrowErrorMatchingInlineSnapshot(
+      `"You specified SSL_CRT_FILE in your env, but the file \\"<PROJECT_ROOT>/packages/docusaurus/src/webpack/__tests__/__fixtures__/nonexistent.crt\\" can't be found."`,
+    );
+  });
+
+  it('throws for invalid key', async () => {
+    process.env.HTTPS = 'true';
+    process.env.SSL_CRT_FILE = path.join(__dirname, '__fixtures__/host.crt');
+    process.env.SSL_KEY_FILE = path.join(__dirname, '__fixtures__/invalid.key');
+    await expect(getHttpsConfig()).rejects.toThrowError(
+      /The certificate key .*[/\\]__fixtures__[/\\]invalid\.key is invalid/,
+    );
+  });
+
+  it('throws for invalid cert', async () => {
+    process.env.HTTPS = 'true';
+    process.env.SSL_CRT_FILE = path.join(__dirname, '__fixtures__/invalid.crt');
+    process.env.SSL_KEY_FILE = path.join(__dirname, '__fixtures__/host.key');
+    await expect(getHttpsConfig()).rejects.toThrowError(
+      /The certificate .*[/\\]__fixtures__[/\\]invalid\.crt is invalid/,
+    );
+  });
+});
diff --git a/website/src/utils/jsUtils.ts b/website/src/utils/jsUtils.ts
index c389b4e397..868a32d061 100644
--- a/website/src/utils/jsUtils.ts
+++ b/website/src/utils/jsUtils.ts
@@ -5,11 +5,6 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-// Inspired by https://github.com/you-dont-need/You-Dont-Need-Lodash-Underscore#_difference
-export function difference<T>(...arrays: T[][]): T[] {
-  return arrays.reduce((a, b) => a.filter((c) => !b.includes(c)));
-}
-
 // Inspired by https://github.com/you-dont-need/You-Dont-Need-Lodash-Underscore#_sortby-and-_orderby
 export function sortBy<T>(
   array: T[],