feat(v2): allow nested sidebar category shorthand syntax

jest.config.js

@@ -27,5 +27,5 @@ module.exports = {
   transform: {
     '^.+\\.[jt]sx?$': 'babel-jest',
   },
-  setupFiles: ['./jest/stylelint-rule-test.js'],
+  setupFiles: ['./jest/stylelint-rule-test.js', 'array-flat-polyfill'],
 };

packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-category-shorthand.js

@@ -0,0 +1,34 @@
+/**
+ * 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.
+ */
+
+module.exports = {
+  docs: [
+    {
+      'level 1': [
+        'a',
+        {
+          'level 2': [
+            {
+              'level 3': [
+                'c',
+                {
+                  'level 4': [
+                    'd',
+                    {
+                      'deeper more more': ['e'],
+                    },
+                  ],
+                },
+              ],
+            },
+            'f',
+          ],
+        },
+      ],
+    },
+  ],
+};

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

@@ -24,6 +24,17 @@ describe('loadSidebars', () => {
     expect(result).toMatchSnapshot();
   });
 
+  test('sidebars shortand and longform lead to exact same sidebar', async () => {
+    const sidebarPath1 = path.join(fixtureDir, 'sidebars-category.js');
+    const sidebarPath2 = path.join(
+      fixtureDir,
+      'sidebars-category-shorthand.js',
+    );
+    const sidebar1 = loadSidebars([sidebarPath1]);
+    const sidebar2 = loadSidebars([sidebarPath2]);
+    expect(sidebar1).toEqual(sidebar2);
+  });
+
   test('sidebars with category but category.items is not an array', async () => {
     const sidebarPath = path.join(
       fixtureDir,
@@ -93,15 +104,6 @@ describe('loadSidebars', () => {
     );
   });
 
-  test('sidebars with invalid sidebar item', async () => {
-    const sidebarPath = path.join(fixtureDir, 'sidebars-invalid-item.json');
-    expect(() =>
-      loadSidebars([sidebarPath]),
-    ).toThrowErrorMatchingInlineSnapshot(
-      `"Unknown sidebar item \\"{\\"a\\":\\"b\\",\\"c\\":\\"d\\"}\\"."`,
-    );
-  });
-
   test('sidebars with unknown sidebar item type', async () => {
     const sidebarPath = path.join(fixtureDir, 'sidebars-unknown-type.json');
     expect(() =>

packages/docusaurus-plugin-content-docs/src/sidebars.ts

@@ -15,8 +15,28 @@ import {
   SidebarItemRaw,
   SidebarItemLink,
   SidebarItemDoc,
+  SidebarCategoryShorthandRaw,
 } from './types';
 
+function isCategoryShorthand(
+  item: SidebarItemRaw,
+): item is SidebarCategoryShorthandRaw {
+  return typeof item !== 'string' && !item.type;
+}
+
+/**
+ * Convert {category1: [item1,item2]} shorthand syntax to long-form syntax
+ */
+function normalizeCategoryShorthand(
+  sidebar: SidebarCategoryShorthandRaw,
+): SidebarItemCategoryRaw[] {
+  return Object.entries(sidebar).map(([label, items]) => ({
+    type: 'category',
+    label,
+    items,
+  }));
+}
+
 /**
  * Check that item contains only allowed keys.
  */
@@ -75,27 +95,29 @@ function assertIsLink(item: any): asserts item is SidebarItemLink {
  * Normalizes recursively item and all its children. Ensures that at the end
  * each item will be an object with the corresponding type.
  */
-function normalizeItem(item: SidebarItemRaw): SidebarItem {
+function normalizeItem(item: SidebarItemRaw): SidebarItem[] {
   if (typeof item === 'string') {
-    return {
-      type: 'doc',
-      id: item,
-    };
+    return [
+      {
+        type: 'doc',
+        id: item,
+      },
+    ];
   }
-  if (!item.type) {
-    throw new Error(`Unknown sidebar item "${JSON.stringify(item)}".`);
+  if (isCategoryShorthand(item)) {
+    return normalizeCategoryShorthand(item).flatMap(normalizeItem);
   }
   switch (item.type) {
     case 'category':
       assertIsCategory(item);
-      return {...item, items: item.items.map(normalizeItem)};
+      return [{...item, items: item.items.flatMap(normalizeItem)}];
     case 'link':
       assertIsLink(item);
-      return item;
+      return [item];
     case 'ref':
     case 'doc':
       assertIsDoc(item);
-      return item;
+      return [item];
     default:
       throw new Error(`Unknown sidebar item type: ${item.type}`);
   }
@@ -107,20 +129,11 @@ function normalizeItem(item: SidebarItemRaw): SidebarItem {
 function normalizeSidebar(sidebars: SidebarRaw): Sidebar {
   return Object.entries(sidebars).reduce(
     (acc: Sidebar, [sidebarId, sidebar]) => {
-      let normalizedSidebar: SidebarItemRaw[];
-
-      if (!Array.isArray(sidebar)) {
-        // Convert sidebar to a more generic structure.
-        normalizedSidebar = Object.entries(sidebar).map(([label, items]) => ({
-          type: 'category',
-          label,
-          items,
-        }));
-      } else {
-        normalizedSidebar = sidebar;
-      }
-
-      acc[sidebarId] = normalizedSidebar.map(normalizeItem);
+      const normalizedSidebar: SidebarItemRaw[] = Array.isArray(sidebar)
+        ? sidebar
+        : normalizeCategoryShorthand(sidebar);
+
+      acc[sidebarId] = normalizedSidebar.flatMap(normalizeItem);
 
       return acc;
     },

packages/docusaurus-plugin-content-docs/src/types.ts

@@ -55,6 +55,7 @@ export type SidebarItem =
 
 export type SidebarItemRaw =
   | string
+  | SidebarCategoryShorthandRaw
   | SidebarItemDoc
   | SidebarItemLink
   | SidebarItemCategoryRaw
@@ -63,13 +64,13 @@ export type SidebarItemRaw =
       [key: string]: any;
     };
 
+export interface SidebarCategoryShorthandRaw {
+  [sidebarCategory: string]: SidebarItemRaw[];
+}
+
 // Sidebar given by user that is not normalized yet. e.g: sidebars.json
 export interface SidebarRaw {
-  [sidebarId: string]:
-    | {
-        [sidebarCategory: string]: SidebarItemRaw[];
-      }
-    | SidebarItemRaw[];
+  [sidebarId: string]: SidebarCategoryShorthandRaw | SidebarItemRaw[];
 }
 
 export interface Sidebar {

packages/docusaurus/package.json

@@ -41,6 +41,7 @@
     "@babel/runtime": "^7.7.4",
     "@docusaurus/utils": "^2.0.0-alpha.48",
     "@endiliey/static-site-generator-webpack-plugin": "^4.0.0",
+    "array-flat-polyfill": "^1.0.1",
     "babel-loader": "^8.0.6",
     "babel-plugin-dynamic-import-node": "^2.3.0",
     "cache-loader": "^4.1.0",

packages/docusaurus/src/index.ts

@@ -5,6 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import 'array-flat-polyfill';
+
 export {build} from './commands/build';
 export {start} from './commands/start';
 export {swizzle} from './commands/swizzle';

tsconfig.json

@@ -2,7 +2,7 @@
   "compilerOptions": {
     "target": "es2017",
     "module": "commonjs",
-    "lib": ["es2017"],
+    "lib": ["es2017","es2019.array"],
     "declaration": true,
     "declarationMap": true,
 

website/docs/sidebar.md

@@ -50,7 +50,7 @@ module.exports = {
 };
 ```
 
-If you don't want to rely on iteration order of JavaScript object keys for the category name, the following sidebar object is also equivalent of the above.
+Keep in mind that EcmaScript does not guarantee `Object.keys({a,b}) === ['a','b']` (yet, this is generally true). If you don't want to rely on iteration order of JavaScript object keys for the category name, the following sidebar object is also equivalent of the above shorthand syntax.
 
 ```js
 // sidebars.js
@@ -221,7 +221,23 @@ module.exports = {
       {
         type: 'category',
         label: 'Docs',
-        items: ['markdown-features', 'sidebar'],
+        items: ['markdown-features', 'sidebar', 'versioning'],
+      },
+    ],
+  },
+};
+```
+
+**Note**: it's possible to use the shorthand syntax to create nested categories:
+
+```js
+// sidebars.js
+module.exports = {
+  docs: {
+    Guides: [
+      'creating-pages',
+      {
+        Docs: ['markdown-features', 'sidebar', 'versioning'],
       },
     ],
   },

website/sidebars.js

@@ -19,9 +19,7 @@ module.exports = {
       'styling-layout',
       'static-assets',
       {
-        type: 'category',
-        label: 'Docs',
-        items: ['markdown-features', 'sidebar', 'versioning'],
+        Docs: ['markdown-features', 'sidebar', 'versioning'],
       },
       'blog',
       'search',