feat(core): async docusaurus.config.js creator function

packages/docusaurus/src/server/__tests__/__fixtures__/configs/configAsync.config.js

@@ -0,0 +1,15 @@
+/**
+ * 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 = Promise.resolve({
+  title: 'Hello',
+  tagline: 'Hello World',
+  organizationName: 'endiliey',
+  projectName: 'hello',
+  baseUrl: '/',
+  url: 'https://docusaurus.io',
+});

packages/docusaurus/src/server/__tests__/__fixtures__/configs/createConfig.config.js

@@ -0,0 +1,17 @@
+/**
+ * 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 = function createConfig() {
+  return {
+    title: 'Hello',
+    tagline: 'Hello World',
+    organizationName: 'endiliey',
+    projectName: 'hello',
+    baseUrl: '/',
+    url: 'https://docusaurus.io',
+  };
+};

packages/docusaurus/src/server/__tests__/__fixtures__/configs/createConfigAsync.config.js

@@ -0,0 +1,20 @@
+/**
+ * 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 = async function createConfig() {
+  await new Promise((resolve) => {
+    setTimeout(resolve, 10);
+  });
+  return {
+    title: 'Hello',
+    tagline: 'Hello World',
+    organizationName: 'endiliey',
+    projectName: 'hello',
+    baseUrl: '/',
+    url: 'https://docusaurus.io',
+  };
+};

packages/docusaurus/src/server/__tests__/__snapshots__/config.test.ts.snap

@@ -11,6 +11,102 @@ If you still want these fields to be in your configuration, put them in the \\"c
 See https://docusaurus.io/docs/docusaurus.config.js/#customfields"
 `;
 
+exports[`loadConfig website with valid async config 1`] = `
+Object {
+  "baseUrl": "/",
+  "baseUrlIssueBanner": true,
+  "customFields": Object {},
+  "i18n": Object {
+    "defaultLocale": "en",
+    "localeConfigs": Object {},
+    "locales": Array [
+      "en",
+    ],
+  },
+  "noIndex": false,
+  "onBrokenLinks": "throw",
+  "onBrokenMarkdownLinks": "warn",
+  "onDuplicateRoutes": "warn",
+  "organizationName": "endiliey",
+  "plugins": Array [],
+  "presets": Array [],
+  "projectName": "hello",
+  "staticDirectories": Array [
+    "static",
+  ],
+  "tagline": "Hello World",
+  "themeConfig": Object {},
+  "themes": Array [],
+  "title": "Hello",
+  "titleDelimiter": "|",
+  "url": "https://docusaurus.io",
+}
+`;
+
+exports[`loadConfig website with valid async config creator function 1`] = `
+Object {
+  "baseUrl": "/",
+  "baseUrlIssueBanner": true,
+  "customFields": Object {},
+  "i18n": Object {
+    "defaultLocale": "en",
+    "localeConfigs": Object {},
+    "locales": Array [
+      "en",
+    ],
+  },
+  "noIndex": false,
+  "onBrokenLinks": "throw",
+  "onBrokenMarkdownLinks": "warn",
+  "onDuplicateRoutes": "warn",
+  "organizationName": "endiliey",
+  "plugins": Array [],
+  "presets": Array [],
+  "projectName": "hello",
+  "staticDirectories": Array [
+    "static",
+  ],
+  "tagline": "Hello World",
+  "themeConfig": Object {},
+  "themes": Array [],
+  "title": "Hello",
+  "titleDelimiter": "|",
+  "url": "https://docusaurus.io",
+}
+`;
+
+exports[`loadConfig website with valid config creator function 1`] = `
+Object {
+  "baseUrl": "/",
+  "baseUrlIssueBanner": true,
+  "customFields": Object {},
+  "i18n": Object {
+    "defaultLocale": "en",
+    "localeConfigs": Object {},
+    "locales": Array [
+      "en",
+    ],
+  },
+  "noIndex": false,
+  "onBrokenLinks": "throw",
+  "onBrokenMarkdownLinks": "warn",
+  "onDuplicateRoutes": "warn",
+  "organizationName": "endiliey",
+  "plugins": Array [],
+  "presets": Array [],
+  "projectName": "hello",
+  "staticDirectories": Array [
+    "static",
+  ],
+  "tagline": "Hello World",
+  "themeConfig": Object {},
+  "themes": Array [],
+  "title": "Hello",
+  "titleDelimiter": "|",
+  "url": "https://docusaurus.io",
+}
+`;
+
 exports[`loadConfig website with valid siteConfig 1`] = `
 Object {
   "baseUrl": "/",

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

@@ -16,45 +16,75 @@ describe('loadConfig', () => {
       'simple-site',
       'docusaurus.config.js',
     );
-    const config = loadConfig(siteDir);
+    const config = await loadConfig(siteDir);
     expect(config).toMatchSnapshot();
     expect(config).not.toEqual({});
   });
 
-  test('website with incomplete siteConfig', () => {
+  test('website with valid config creator function', async () => {
+    const siteDir = path.join(
+      __dirname,
+      '__fixtures__',
+      'configs',
+      'createConfig.config.js',
+    );
+    const config = await loadConfig(siteDir);
+    expect(config).toMatchSnapshot();
+    expect(config).not.toEqual({});
+  });
+
+  test('website with valid async config', async () => {
+    const siteDir = path.join(
+      __dirname,
+      '__fixtures__',
+      'configs',
+      'configAsync.config.js',
+    );
+    const config = await loadConfig(siteDir);
+    expect(config).toMatchSnapshot();
+    expect(config).not.toEqual({});
+  });
+
+  test('website with valid async config creator function', async () => {
+    const siteDir = path.join(
+      __dirname,
+      '__fixtures__',
+      'configs',
+      'createConfigAsync.config.js',
+    );
+    const config = await loadConfig(siteDir);
+    expect(config).toMatchSnapshot();
+    expect(config).not.toEqual({});
+  });
+
+  test('website with incomplete siteConfig', async () => {
     const siteDir = path.join(
       __dirname,
       '__fixtures__',
       'bad-site',
       'docusaurus.config.js',
     );
-    expect(() => {
-      loadConfig(siteDir);
-    }).toThrowErrorMatchingSnapshot();
+    await expect(loadConfig(siteDir)).rejects.toThrowErrorMatchingSnapshot();
   });
 
-  test('website with useless field (wrong field) in siteConfig', () => {
+  test('website with useless field (wrong field) in siteConfig', async () => {
     const siteDir = path.join(
       __dirname,
       '__fixtures__',
       'wrong-site',
       'docusaurus.config.js',
     );
-    expect(() => {
-      loadConfig(siteDir);
-    }).toThrowErrorMatchingSnapshot();
+    await expect(loadConfig(siteDir)).rejects.toThrowErrorMatchingSnapshot();
   });
 
-  test('website with no siteConfig', () => {
+  test('website with no siteConfig', async () => {
     const siteDir = path.join(
       __dirname,
       '__fixtures__',
       'nonExisting',
       'docusaurus.config.js',
     );
-    expect(() => {
-      loadConfig(siteDir);
-    }).toThrowError(
+    await expect(loadConfig(siteDir)).rejects.toThrowError(
       /Config file at "(.*?)__fixtures__[/\\]nonExisting[/\\]docusaurus.config.js" not found.$/,
     );
   });

packages/docusaurus/src/server/config.ts

@@ -10,11 +10,23 @@ import importFresh from 'import-fresh';
 import {DocusaurusConfig} from '@docusaurus/types';
 import {validateConfig} from './configValidation';
 
-export default function loadConfig(configPath: string): DocusaurusConfig {
+export default async function loadConfig(
+  configPath: string,
+): Promise<DocusaurusConfig> {
   if (!fs.existsSync(configPath)) {
     throw new Error(`Config file at "${configPath}" not found.`);
   }
 
-  const loadedConfig = importFresh(configPath) as Partial<DocusaurusConfig>;
+  const importedConfig = importFresh(configPath) as
+    | Partial<DocusaurusConfig>
+    | Promise<Partial<DocusaurusConfig>>
+    | (() => Partial<DocusaurusConfig>)
+    | (() => Promise<Partial<DocusaurusConfig>>);
+
+  const loadedConfig =
+    importedConfig instanceof Function
+      ? await importedConfig()
+      : await importedConfig;
+
   return validateConfig(loadedConfig);
 }

website/docs/api/docusaurus.config.js.md

@@ -11,6 +11,41 @@ slug: /api/docusaurus-config
 
 `docusaurus.config.js` contains configurations for your site and is placed in the root directory of your site.
 
+It usually exports a site configuration object:
+
+```js title="docusaurus.config.js"
+module.exports = {
+  // site config...
+};
+```
+
+<details>
+<summary>Config files also support config creator functions and async code.</summary>
+
+```js title="docusaurus.config.js"
+module.exports = function configCreator() {
+  return {
+    // site config...
+  };
+};
+```
+
+```js title="docusaurus.config.js"
+module.exports = async function configCreatorAsync() {
+  return {
+    // site config...
+  };
+};
+```
+
+```js title="docusaurus.config.js"
+module.exports = Promise.resolve({
+  // site config...
+});
+```
+
+</details>
+
 ## Required fields {#required-fields}
 
 ### `title` {#title}

website/docusaurus.config.js

@@ -515,4 +515,12 @@ const config = {
     }),
 };
 
-module.exports = config;
+// TODO temporary dogfood async config, remove soon
+async function createConfig() {
+  await new Promise((resolve) => {
+    setTimeout(resolve, 0);
+  });
+  return config;
+}
+
+module.exports = createConfig;