test: improve test coverage (#6387)

* test: improve test coverage

* fix

* use posixPath

.stylelintignore

@@ -1,4 +1,3 @@
-__fixtures__
 build
 coverage
 examples/

packages/docusaurus-cssnano-preset/src/remove-overridden-custom-properties/__tests__/__fixtures__/important_rule.css

@@ -1,3 +1,4 @@
+/* stylelint-disable docusaurus/copyright-header, declaration-block-no-duplicate-custom-properties */
 :root {
   --color-primary: red;
   --color-secondary: green;

packages/docusaurus-cssnano-preset/src/remove-overridden-custom-properties/__tests__/__fixtures__/normal.css

@@ -1,3 +1,4 @@
+/* stylelint-disable docusaurus/copyright-header, declaration-block-no-duplicate-custom-properties */
 :root {
   --color-primary: red;
   --color-primary: red;
@@ -5,3 +6,8 @@
   --color-primary: blue;
   --color-header: gray;
 }
+
+.non-root {
+  --color-primary: red;
+  --color-primary: red;
+}

packages/docusaurus-cssnano-preset/src/remove-overridden-custom-properties/__tests__/__snapshots__/index.test.js.snap

@@ -1,16 +1,23 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`remove-overridden-custom-properties overridden custom properties should be removed 1`] = `
-":root {
+"/* stylelint-disable docusaurus/copyright-header, declaration-block-no-duplicate-custom-properties */
+:root {
   --color-secondary: green;
   --color-primary: blue;
   --color-header: gray;
 }
+
+.non-root {
+  --color-primary: red;
+  --color-primary: red;
+}
 "
 `;
 
 exports[`remove-overridden-custom-properties overridden custom properties with \`!important\` rule should not be removed 1`] = `
-":root {
+"/* stylelint-disable docusaurus/copyright-header, declaration-block-no-duplicate-custom-properties */
+:root {
   --color-primary: blue;
   --color-header: gray !important;
   --color-secondary: yellow !important;

packages/docusaurus-cssnano-preset/src/remove-overridden-custom-properties/index.js

@@ -22,8 +22,9 @@ module.exports = function creator() {
         return;
       }
 
-      const sameProperties =
+      const sameProperties = decl.parent.nodes.filter(
-        decl.parent.nodes.filter((n) => n.prop === decl.prop) || [];
+        (n) => n.prop === decl.prop,
+      );
       const hasImportantProperties = sameProperties.some((p) =>
         Object.prototype.hasOwnProperty.call(p, 'important'),
       );

packages/docusaurus-plugin-client-redirects/src/__tests__/collectRedirects.test.ts

@@ -260,6 +260,25 @@ describe('collectRedirects', () => {
     ]);
   });
 
+  test('should allow returning string / undefined', () => {
+    expect(
+      collectRedirects(
+        createTestPluginContext(
+          {
+            createRedirects: (routePath) => {
+              if (routePath === '/') {
+                return `${routePath}foo`;
+              }
+              return undefined;
+            },
+          },
+          ['/', '/testpath', '/otherPath.html'],
+        ),
+        undefined,
+      ),
+    ).toEqual([{from: '/foo', to: '/'}]);
+  });
+
   test('should throw if redirect creator creates invalid redirects', () => {
     expect(() =>
       collectRedirects(

packages/docusaurus-plugin-content-blog/src/__tests__/__fixtures__/website/blog/complex-slug.md

@@ -1,7 +1,8 @@
 ---
 slug: /hey/my super path/héllô
 title: Complex Slug
-date: 2020-08-16
+# This date is not YAML date, but we can still use it.
+date: 2020/08/16
 ---
 
 complex url slug

packages/docusaurus-plugin-content-blog/src/__tests__/__snapshots__/feed.test.ts.snap

@@ -1,7 +1,10 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`blogFeed atom shows feed item for each post 1`] = `
-"<?xml version=\\"1.0\\" encoding=\\"utf-8\\"?>
+Array [
+  Array [
+    "build/blog/atom.xml",
+    "<?xml version=\\"1.0\\" encoding=\\"utf-8\\"?>
 <feed xmlns=\\"http://www.w3.org/2005/Atom\\">
     <id>https://docusaurus.io/myBaseUrl/blog</id>
     <title>Hello Blog</title>
@@ -83,11 +86,16 @@ exports[`blogFeed atom shows feed item for each post 1`] = `
             <name>Sébastien Lorber (translated)</name>
         </author>
     </entry>
-</feed>"
+</feed>",
+  ],
+]
 `;
 
 exports[`blogFeed json shows feed item for each post 1`] = `
-"{
+Array [
+  Array [
+    "build/blog/feed.json",
+    "{
     \\"version\\": \\"https://jsonfeed.org/version/1\\",
     \\"title\\": \\"Hello Blog\\",
     \\"home_page_url\\": \\"https://docusaurus.io/myBaseUrl/blog\\",
@@ -163,11 +171,16 @@ exports[`blogFeed json shows feed item for each post 1`] = `
             }
         }
     ]
-}"
+}",
+  ],
+]
 `;
 
 exports[`blogFeed rss shows feed item for each post 1`] = `
-"<?xml version=\\"1.0\\" encoding=\\"utf-8\\"?>
+Array [
+  Array [
+    "build/blog/rss.xml",
+    "<?xml version=\\"1.0\\" encoding=\\"utf-8\\"?>
 <rss version=\\"2.0\\" xmlns:dc=\\"http://purl.org/dc/elements/1.1/\\" xmlns:content=\\"http://purl.org/rss/1.0/modules/content/\\">
     <channel>
         <title>Hello Blog</title>
@@ -240,5 +253,7 @@ exports[`blogFeed rss shows feed item for each post 1`] = `
             <content:encoded><![CDATA[<p>Happy birthday! (translated)</p>]]></content:encoded>
         </item>
     </channel>
-</rss>"
+</rss>",
+  ],
+]
 `;

packages/docusaurus-plugin-content-blog/src/__tests__/blogUtils.test.ts

@@ -5,7 +5,24 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {parseBlogFileName} from '../blogUtils';
+import {truncate, parseBlogFileName} from '../blogUtils';
+
+describe('truncate', () => {
+  test('truncates texts', () => {
+    expect(
+      truncate('aaa\n<!-- truncate -->\nbbb\nccc', /<!-- truncate -->/),
+    ).toEqual('aaa\n');
+    expect(
+      truncate('\n<!-- truncate -->\nbbb\nccc', /<!-- truncate -->/),
+    ).toEqual('\n');
+  });
+  test('leaves texts without markers', () => {
+    expect(truncate('aaa\nbbb\nccc', /<!-- truncate -->/)).toEqual(
+      'aaa\nbbb\nccc',
+    );
+    expect(truncate('', /<!-- truncate -->/)).toEqual('');
+  });
+});
 
 describe('parseBlogFileName', () => {
   test('parse file', () => {

packages/docusaurus-plugin-content-blog/src/__tests__/feed.test.ts

@@ -6,12 +6,12 @@
  */
 
 import path from 'path';
-import {generateBlogFeed} from '../feed';
+import fs from 'fs-extra';
+import {createBlogFeedFiles} from '../feed';
 import type {LoadContext, I18n} from '@docusaurus/types';
 import type {BlogContentPaths} from '../types';
 import {DEFAULT_OPTIONS} from '../pluginOptionSchema';
 import {generateBlogPosts} from '../blogUtils';
-import type {Feed} from 'feed';
 import type {PluginOptions} from '@docusaurus/plugin-content-blog';
 
 const DefaultI18N: I18n = {
@@ -36,23 +36,26 @@ function getBlogContentPaths(siteDir: string): BlogContentPaths {
 async function testGenerateFeeds(
   context: LoadContext,
   options: PluginOptions,
-): Promise<Feed | null> {
+): Promise<void> {
   const blogPosts = await generateBlogPosts(
     getBlogContentPaths(context.siteDir),
     context,
     options,
   );
 
-  return generateBlogFeed({
+  await createBlogFeedFiles({
     blogPosts,
     options,
     siteConfig: context.siteConfig,
+    outDir: 'build',
   });
 }
 
 describe('blogFeed', () => {
   (['atom', 'rss', 'json'] as const).forEach((feedType) => {
     describe(`${feedType}`, () => {
+      const fsMock = jest.spyOn(fs, 'outputFile').mockImplementation(() => {});
+
       test('should not show feed without posts', async () => {
         const siteDir = __dirname;
         const siteConfig = {
@@ -62,7 +65,7 @@ describe('blogFeed', () => {
           favicon: 'image/favicon.ico',
         };
 
-        const feed = await testGenerateFeeds(
+        await testGenerateFeeds(
           {
             siteDir,
             siteConfig,
@@ -83,7 +86,8 @@ describe('blogFeed', () => {
           } as PluginOptions,
         );
 
-        expect(feed).toEqual(null);
+        expect(fsMock).toBeCalledTimes(0);
+        fsMock.mockClear();
       });
 
       test('shows feed item for each post', async () => {
@@ -96,7 +100,7 @@ describe('blogFeed', () => {
           favicon: 'image/favicon.ico',
         };
 
-        const feed = await testGenerateFeeds(
+        await testGenerateFeeds(
           {
             siteDir,
             siteConfig,
@@ -119,22 +123,8 @@ describe('blogFeed', () => {
           } as PluginOptions,
         );
 
-        let feedContent = '';
+        expect(fsMock.mock.calls).toMatchSnapshot();
-        switch (feedType) {
+        fsMock.mockClear();
-          case 'rss':
-            feedContent = feed.rss2();
-            break;
-          case 'json':
-            feedContent = feed.json1();
-            break;
-          case 'atom':
-            feedContent = feed.atom1();
-            break;
-          default:
-            break;
-        }
-
-        expect(feedContent).toMatchSnapshot();
       });
     });
   });

packages/docusaurus-plugin-content-blog/src/__tests__/index.test.ts

@@ -204,7 +204,7 @@ describe('loadBlog', () => {
       date: new Date('2020-08-16'),
       formattedDate: 'August 16, 2020',
       frontMatter: {
-        date: new Date('2020-08-16'),
+        date: '2020/08/16',
         slug: '/hey/my super path/héllô',
         title: 'Complex Slug',
       },

packages/docusaurus-plugin-content-blog/src/feed.ts

@@ -7,7 +7,7 @@
 
 import {Feed, type Author as FeedAuthor, type Item as FeedItem} from 'feed';
 import type {BlogPost} from './types';
-import {normalizeUrl, mdxToHtml} from '@docusaurus/utils';
+import {normalizeUrl, mdxToHtml, posixPath} from '@docusaurus/utils';
 import type {DocusaurusConfig} from '@docusaurus/types';
 import path from 'path';
 import fs from 'fs-extra';
@@ -30,7 +30,7 @@ function mdxToFeedContent(mdxContent: string): string | undefined {
   }
 }
 
-export async function generateBlogFeed({
+async function generateBlogFeed({
   blogPosts,
   options,
   siteConfig,
@@ -47,9 +47,7 @@ export async function generateBlogFeed({
   const {url: siteUrl, baseUrl, title, favicon} = siteConfig;
   const blogBaseUrl = normalizeUrl([siteUrl, baseUrl, routeBasePath]);
 
-  const updated =
+  const updated = blogPosts[0] && blogPosts[0].metadata.date;
-    (blogPosts[0] && blogPosts[0].metadata.date) ||
-    new Date('2015-10-25T16:29:00.000-07:00'); // weird legacy magic date
 
   const feed = new Feed({
     id: blogBaseUrl,
@@ -118,7 +116,10 @@ async function createBlogFeedFile({
     }
   })();
   try {
-    await fs.outputFile(path.join(generatePath, feedPath), feedContent);
+    await fs.outputFile(
+      posixPath(path.join(generatePath, feedPath)),
+      feedContent,
+    );
   } catch (err) {
     throw new Error(`Generating ${feedType} feed failed: ${err}.`);
   }

packages/docusaurus-plugin-content-docs/src/sidebars/__tests__/generator.test.ts

@@ -201,7 +201,9 @@ describe('DefaultSidebarItemsGenerator', () => {
           source: 'guide1.md',
           sourceDirName: '02-Guides',
           sidebarPosition: 1,
-          frontMatter: {},
+          frontMatter: {
+            sidebar_class_name: 'foo',
+          },
         },
         {
           id: 'nested-guide',
@@ -250,7 +252,7 @@ describe('DefaultSidebarItemsGenerator', () => {
           id: 'guides-index',
         },
         items: [
-          {type: 'doc', id: 'guide1'},
+          {type: 'doc', id: 'guide1', className: 'foo'},
           {
             type: 'category',
             label: 'SubGuides (metadata file label)',
@@ -278,12 +280,17 @@ describe('DefaultSidebarItemsGenerator', () => {
       'subfolder/subsubfolder/subsubsubfolder2/_category_.yml': {
         position: 2,
         label: 'subsubsubfolder2 (_category_.yml label)',
+        className: 'bar',
       },
       'subfolder/subsubfolder/subsubsubfolder3/_category_.json': {
         position: 1,
         label: 'subsubsubfolder3 (_category_.json label)',
         collapsible: false,
         collapsed: false,
+        link: {
+          type: 'doc',
+          id: 'doc1', // This is a "fully-qualified" ID that can't be found locally
+        },
       },
     });
 
@@ -367,6 +374,10 @@ describe('DefaultSidebarItemsGenerator', () => {
         label: 'subsubsubfolder3 (_category_.json label)',
         collapsed: false,
         collapsible: false,
+        link: {
+          id: 'doc1',
+          type: 'doc',
+        },
         items: [
           {type: 'doc', id: 'doc8'},
           {type: 'doc', id: 'doc7'},
@@ -377,6 +388,7 @@ describe('DefaultSidebarItemsGenerator', () => {
         label: 'subsubsubfolder2 (_category_.yml label)',
         collapsed: true,
         collapsible: true,
+        className: 'bar',
         items: [{type: 'doc', id: 'doc6'}],
       },
       {type: 'doc', id: 'doc1'},

packages/docusaurus-plugin-content-docs/src/sidebars/__tests__/processor.test.ts

@@ -102,8 +102,8 @@ describe('processSidebars', () => {
             slug: 'category-generated-index-slug',
             permalink: 'category-generated-index-permalink',
           },
-          collapsed: false,
+          collapsed: true, // A suspicious bad config that will be normalized
-          collapsible: true,
+          collapsible: false,
           items: [
             {type: 'doc', id: 'doc2'},
             {type: 'autogenerated', dirName: 'dir1'},
@@ -172,7 +172,7 @@ describe('processSidebars', () => {
             permalink: 'category-generated-index-permalink',
           },
           collapsed: false,
-          collapsible: true,
+          collapsible: false,
           items: [{type: 'doc', id: 'doc2'}, ...StaticGeneratedSidebarSlice],
         },
         {type: 'link', href: 'https://facebook.com', label: 'FB'},

packages/docusaurus-plugin-content-docs/src/sidebars/__tests__/utils.test.ts

@@ -96,6 +96,14 @@ describe('createSidebarsUtils', () => {
   ];
 
   const sidebar4: Sidebar = [
+    {
+      type: 'category',
+      items: [
+        {type: 'link', href: 'https://facebook.com'},
+        {type: 'link', href: 'https://reactjs.org'},
+        {type: 'link', href: 'https://docusaurus.io'},
+      ],
+    },
     {
       type: 'category',
       collapsed: false,

packages/docusaurus-theme-common/src/utils/__tests__/codeBlockUtils.test.ts

@@ -5,7 +5,11 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {parseCodeBlockTitle} from '../codeBlockUtils';
+import {
+  parseCodeBlockTitle,
+  parseLanguage,
+  parseLines,
+} from '../codeBlockUtils';
 
 describe('parseCodeBlockTitle', () => {
   test('should parse double quote delimited title', () => {
@@ -52,3 +56,227 @@ describe('parseCodeBlockTitle', () => {
     );
   });
 });
+
+describe('parseLanguage', () => {
+  test('behaves correctly', () => {
+    expect(parseLanguage('language-foo xxx yyy')).toEqual('foo');
+    expect(parseLanguage('xxxxx language-foo yyy')).toEqual('foo');
+    expect(parseLanguage('xx-language-foo yyyy')).toBeUndefined();
+    expect(parseLanguage('xxx yyy zzz')).toBeUndefined();
+  });
+});
+
+describe('parseLines', () => {
+  test('does not parse content with metastring', () => {
+    expect(parseLines('aaaaa\nbbbbb', '{1}', 'js')).toMatchInlineSnapshot(`
+      Object {
+        "code": "aaaaa
+      bbbbb",
+        "highlightLines": Array [
+          0,
+        ],
+      }
+    `);
+    expect(
+      parseLines(
+        `// highlight-next-line
+aaaaa
+bbbbb`,
+        '{1}',
+        'js',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "// highlight-next-line
+      aaaaa
+      bbbbb",
+        "highlightLines": Array [
+          0,
+        ],
+      }
+    `);
+    expect(
+      parseLines(
+        `aaaaa
+bbbbb`,
+        '{1}',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "aaaaa
+      bbbbb",
+        "highlightLines": Array [
+          0,
+        ],
+      }
+    `);
+  });
+  test('does not parse content with no language', () => {
+    expect(
+      parseLines(
+        `// highlight-next-line
+aaaaa
+bbbbb`,
+        '',
+        undefined,
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "// highlight-next-line
+      aaaaa
+      bbbbb",
+        "highlightLines": Array [],
+      }
+    `);
+  });
+  test('removes lines correctly', () => {
+    expect(
+      parseLines(
+        `// highlight-next-line
+aaaaa
+bbbbb`,
+        '',
+        'js',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "aaaaa
+      bbbbb",
+        "highlightLines": Array [
+          0,
+        ],
+      }
+    `);
+    expect(
+      parseLines(
+        `// highlight-start
+aaaaa
+// highlight-end
+bbbbb`,
+        '',
+        'js',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "aaaaa
+      bbbbb",
+        "highlightLines": Array [
+          0,
+        ],
+      }
+    `);
+    expect(
+      parseLines(
+        `// highlight-start
+// highlight-next-line
+aaaaa
+bbbbbbb
+// highlight-next-line
+// highlight-end
+bbbbb`,
+        '',
+        'js',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "aaaaa
+      bbbbbbb
+      bbbbb",
+        "highlightLines": Array [
+          0,
+          2,
+          0,
+          1,
+        ],
+      }
+    `);
+  });
+  test('respects language', () => {
+    expect(
+      parseLines(
+        `# highlight-next-line
+aaaaa
+bbbbb`,
+        '',
+        'js',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "# highlight-next-line
+      aaaaa
+      bbbbb",
+        "highlightLines": Array [],
+      }
+    `);
+    expect(
+      parseLines(
+        `/* highlight-next-line */
+aaaaa
+bbbbb`,
+        '',
+        'py',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "/* highlight-next-line */
+      aaaaa
+      bbbbb",
+        "highlightLines": Array [],
+      }
+    `);
+    expect(
+      parseLines(
+        `// highlight-next-line
+aaaa
+/* highlight-next-line */
+bbbbb
+# highlight-next-line
+ccccc
+<!-- highlight-next-line -->
+dddd`,
+        '',
+        'py',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "// highlight-next-line
+      aaaa
+      /* highlight-next-line */
+      bbbbb
+      ccccc
+      <!-- highlight-next-line -->
+      dddd",
+        "highlightLines": Array [
+          4,
+        ],
+      }
+    `);
+    expect(
+      parseLines(
+        `// highlight-next-line
+aaaa
+/* highlight-next-line */
+bbbbb
+# highlight-next-line
+ccccc
+<!-- highlight-next-line -->
+dddd`,
+        '',
+        '',
+      ),
+    ).toMatchInlineSnapshot(`
+      Object {
+        "code": "aaaa
+      bbbbb
+      ccccc
+      dddd",
+        "highlightLines": Array [
+          0,
+          1,
+          2,
+          3,
+        ],
+      }
+    `);
+  });
+});

packages/docusaurus-theme-common/src/utils/__tests__/jsUtils.test.ts

@@ -5,7 +5,27 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {uniq} from '../jsUtils';
+import {uniq, duplicates} from '../jsUtils';
+
+describe('duplicates', () => {
+  test('gets duplicate values', () => {
+    expect(duplicates(['a', 'b', 'c', 'd'])).toEqual([]);
+    expect(duplicates(['a', 'b', 'b', 'b'])).toEqual(['b', 'b']);
+    expect(duplicates(['c', 'b', 'b', 'c'])).toEqual(['b', 'c']);
+    expect(duplicates([{a: 1}, {a: 1}, {a: 1}])).toEqual([]);
+  });
+  test('accepts custom comparator', () => {
+    expect(duplicates([{a: 1}, {a: 1}, {a: 1}], (a, b) => a.a === b.a)).toEqual(
+      [{a: 1}, {a: 1}],
+    );
+    expect(duplicates(['a', 'b', 'c', 'd'], (a, b) => a !== b)).toEqual([
+      'a',
+      'b',
+      'c',
+      'd',
+    ]);
+  });
+});
 
 describe('uniq', () => {
   test('remove duplicate primitives', () => {

packages/docusaurus-theme-common/src/utils/__tests__/regexpUtils.test.ts

@@ -0,0 +1,21 @@
+/**
+ * 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 {isRegexpStringMatch} from '../regexpUtils';
+
+describe('isRegexpStringMatch', () => {
+  test('behaves correctly', () => {
+    expect(isRegexpStringMatch(undefined, 'foo')).toEqual(false);
+    expect(isRegexpStringMatch('bar', undefined)).toEqual(false);
+    expect(isRegexpStringMatch('foo', 'bar')).toEqual(false);
+    expect(isRegexpStringMatch('foo', 'foo')).toEqual(true);
+    expect(isRegexpStringMatch('fooooooooooo', 'foo')).toEqual(false);
+    expect(isRegexpStringMatch('foo', 'fooooooo')).toEqual(true);
+    expect(isRegexpStringMatch('f.*o', 'fggo')).toEqual(true);
+    expect(isRegexpStringMatch('FOO', 'foo')).toEqual(true);
+  });
+});

packages/docusaurus-theme-common/src/utils/__tests__/searchUtils.test.ts

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {docVersionSearchTag} from '../searchUtils';
+
+describe('docVersionSearchTag', () => {
+  test('behaves correctly', () => {
+    expect(docVersionSearchTag('foo', 'bar')).toEqual('docs-foo-bar');
+  });
+});

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

@@ -6,7 +6,7 @@
  */
 
 /**
- * Utility to convert an optional string into a Regex case sensitive and global
+ * Utility to convert an optional string into a Regex case insensitive and global
  */
 export function isRegexpStringMatch(
   regexAsString?: string,

packages/docusaurus-theme-translations/src/__tests__/index.test.ts

@@ -14,13 +14,26 @@ import {
 
 describe('codeTranslationLocalesToTry', () => {
   test('should return appropriate locale lists', () => {
-    expect(codeTranslationLocalesToTry('fr')).toEqual(['fr', 'fr-FR']);
+    expect(codeTranslationLocalesToTry('fr')).toEqual([
+      'fr',
+      'fr-FR',
+      'fr-Latn',
+    ]);
     expect(codeTranslationLocalesToTry('fr-FR')).toEqual(['fr-FR', 'fr']);
     // Note: "pt" is expanded into "pt-BR", not "pt-PT", as "pt-BR" is more widely used!
     // See https://github.com/facebook/docusaurus/pull/4536#issuecomment-810088783
-    expect(codeTranslationLocalesToTry('pt')).toEqual(['pt', 'pt-BR']);
+    expect(codeTranslationLocalesToTry('pt')).toEqual([
+      'pt',
+      'pt-BR',
+      'pt-Latn',
+    ]);
     expect(codeTranslationLocalesToTry('pt-BR')).toEqual(['pt-BR', 'pt']);
     expect(codeTranslationLocalesToTry('pt-PT')).toEqual(['pt-PT', 'pt']);
+    expect(codeTranslationLocalesToTry('zh')).toEqual([
+      'zh',
+      'zh-CN',
+      'zh-Hans',
+    ]);
   });
 });
 
@@ -123,4 +136,17 @@ describe('readDefaultCodeTranslationMessages', () => {
       }),
     ).resolves.toEqual(await readAsJSON('en'));
   });
+
+  test('default locale', async () => {
+    await expect(
+      readDefaultCodeTranslationMessages({
+        locale: 'zh',
+        name: 'plugin-pwa',
+      }),
+    ).resolves.toEqual({
+      'theme.PwaReloadPopup.closeButtonAriaLabel': '关闭',
+      'theme.PwaReloadPopup.info': '有可用的新版本',
+      'theme.PwaReloadPopup.refreshButtonText': '刷新',
+    });
+  });
 });

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

@@ -14,16 +14,17 @@ function getDefaultLocalesDirPath(): string {
 
 // Return an ordered list of locales we should try
 export function codeTranslationLocalesToTry(locale: string): string[] {
-  const intlLocale = Intl.Locale ? new Intl.Locale(locale) : undefined;
+  const intlLocale = new Intl.Locale(locale);
-  if (!intlLocale) {
-    return [locale];
-  }
   // if locale is just a simple language like "pt", we want to fallback to pt-BR (not pt-PT!)
   // see https://github.com/facebook/docusaurus/pull/4536#issuecomment-810088783
   if (intlLocale.language === locale) {
     const maximizedLocale = intlLocale.maximize(); // pt-Latn-BR`
-    // ["pt","pt-BR"]
+    // ["pt","pt-BR"]; ["zh", "zh-Hans"]
-    return [locale, `${maximizedLocale.language}-${maximizedLocale.region}`];
+    return [
+      locale,
+      `${maximizedLocale.language}-${maximizedLocale.region}`,
+      `${maximizedLocale.language}-${maximizedLocale.script}`,
+    ];
   }
   // if locale is like "pt-BR", we want to fallback to "pt"
   else {

packages/docusaurus/src/client/__tests__/normalizeLocation.test.ts

@@ -35,6 +35,8 @@ describe('normalizeLocation', () => {
   });
 
   test('untouched pathnames', () => {
+    const replaceMock = jest.spyOn(String.prototype, 'replace');
+
     expect(
       normalizeLocation({
         pathname: '/docs/introduction',
@@ -47,6 +49,20 @@ describe('normalizeLocation', () => {
       hash: '#features',
     });
 
+    // For the sake of testing memoization
+    expect(
+      normalizeLocation({
+        pathname: '/docs/introduction',
+        search: '',
+        hash: '#features',
+      }),
+    ).toEqual({
+      pathname: '/docs/introduction',
+      search: '',
+      hash: '#features',
+    });
+    expect(replaceMock).toBeCalledTimes(1);
+
     expect(
       normalizeLocation({
         pathname: '/docs/introduction/foo.html',

packages/docusaurus/src/server/presets/index.ts

@@ -23,7 +23,7 @@ export default function loadPresets(context: LoadContext): {
   // declares the dependency on these presets.
   const presetRequire = createRequire(context.siteConfigPath);
 
-  const presets: PresetConfig[] = (context.siteConfig || {}).presets || [];
+  const presets: PresetConfig[] = context.siteConfig.presets || [];
   const unflatPlugins: PluginConfig[][] = [];
   const unflatThemes: PluginConfig[][] = [];