feat(core): allow plugin/preset config to contain false/null (#7124)

packages/docusaurus-types/src/index.d.ts

@@ -27,9 +27,15 @@ export type PluginConfig =
   | string
   | [string, PluginOptions]
   | [PluginModule, PluginOptions]
-  | PluginModule;
+  | PluginModule
+  | false
+  | null;
 
-export type PresetConfig = string | [string, {[key: string]: unknown}];
+export type PresetConfig =
+  | string
+  | [string, {[key: string]: unknown}]
+  | false
+  | null;
 
 export type ThemeConfig = {
   [key: string]: unknown;

packages/docusaurus/src/server/__tests__/configValidation.test.ts

@@ -173,6 +173,7 @@ describe('normalizeConfig', () => {
       'should accept [function, object] for plugin',
       [[() => {}, {it: 'should work'}]],
     ],
+    ['should accept false/null for plugin', [false, null, 'classic']],
   ])(`%s for the input of: %p`, (_message, plugins) => {
     expect(() => {
       normalizeConfig({
@@ -211,6 +212,7 @@ describe('normalizeConfig', () => {
       'should accept [function, object] for theme',
       [[function theme() {}, {it: 'should work'}]],
     ],
+    ['should accept false/null for themes', [false, null, 'classic']],
   ])(`%s for the input of: %p`, (_message, themes) => {
     expect(() => {
       normalizeConfig({
@@ -254,6 +256,14 @@ describe('normalizeConfig', () => {
     `);
   });
 
+  it('accepts presets as false / null', () => {
+    expect(() => {
+      normalizeConfig({
+        presets: [false, null, 'classic'],
+      });
+    }).not.toThrow();
+  });
+
   it("throws error if scripts doesn't have src", () => {
     expect(() => {
       normalizeConfig({

packages/docusaurus/src/server/configValidation.ts

@@ -71,7 +71,7 @@ function createPluginSchema(theme: boolean) {
         Joi.array()
           .ordered(Joi.string().required(), Joi.object().required())
           .length(2),
-        Joi.bool().equal(false), // In case of conditional adding of plugins.
+        Joi.any().valid(false, null),
       )
       // @ts-expect-error: bad lib def, doesn't recognize an array of reports
       .error((errors) => {
@@ -119,6 +119,7 @@ const PresetSchema = Joi.alternatives()
     Joi.array()
       .items(Joi.string().required(), Joi.object().required())
       .length(2),
+    Joi.any().valid(false, null),
   )
   .messages({
     'alternatives.types': `{#label} does not look like a valid preset config. A preset config entry should be one of:

packages/docusaurus/src/server/plugins/__tests__/__fixtures__/presets/preset-mixed.js

@@ -7,7 +7,7 @@
 
 module.exports = function preset(context, opts = {}) {
   return {
-    themes: [['@docusaurus/theme-classic', opts.test]],
+    themes: [['@docusaurus/theme-classic', opts.test], null],
-    plugins: [['@docusaurus/plugin-test', opts.test]],
+    plugins: [['@docusaurus/plugin-test', opts.test], false],
   };
 };

packages/docusaurus/src/server/plugins/__tests__/__snapshots__/presets.test.ts.snap

@@ -107,6 +107,7 @@ exports[`loadPresets mixed form with themes 1`] = `
       "@docusaurus/plugin-test",
       undefined,
     ],
+    false,
   ],
   "themes": [
     [
@@ -121,6 +122,7 @@ exports[`loadPresets mixed form with themes 1`] = `
       "@docusaurus/theme-classic",
       undefined,
     ],
+    null,
   ],
 }
 `;

packages/docusaurus/src/server/plugins/configs.ts

@@ -17,7 +17,7 @@ import type {
 } from '@docusaurus/types';
 
 async function normalizePluginConfig(
-  pluginConfig: PluginConfig,
+  pluginConfig: Exclude<PluginConfig, false | null>,
   configPath: string,
   pluginRequire: NodeRequire,
 ): Promise<NormalizedPluginConfig> {
@@ -120,7 +120,7 @@ export async function loadPluginConfigs(
     // Site config should be the highest priority.
     ...standalonePlugins,
     ...standaloneThemes,
-  ];
+  ].filter(<T>(x: T | null | false): x is T => Boolean(x));
   return Promise.all(
     pluginConfigs.map((pluginConfig) =>
       normalizePluginConfig(

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

@@ -33,6 +33,9 @@ export async function loadPresets(
   presets.forEach((presetItem) => {
     let presetModuleImport: string;
     let presetOptions = {};
+    if (!presetItem) {
+      return;
+    }
     if (typeof presetItem === 'string') {
       presetModuleImport = presetItem;
     } else {
@@ -53,10 +56,10 @@ export async function loadPresets(
     );
 
     if (preset.plugins) {
-      plugins.push(...preset.plugins.filter(Boolean));
+      plugins.push(...preset.plugins);
     }
     if (preset.themes) {
-      themes.push(...preset.themes.filter(Boolean));
+      themes.push(...preset.themes);
     }
   });