refactor(v2): add typing for pages plugin (#1813)

* refactor(v2): add typing for pages plugin

* misc: new lines

packages/docusaurus-plugin-content-pages/src/index.ts

@@ -0,0 +1,84 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import globby from 'globby';
+import fs from 'fs';
+import path from 'path';
+import {encodePath, fileToPath} from '@docusaurus/utils';
+import {LoadContext, Plugin} from '@docusaurus/types';
+
+import {PluginOptions, LoadedContent} from './types';
+
+const DEFAULT_OPTIONS: PluginOptions = {
+  path: 'src/pages', // Path to data on filesystem, relative to site dir.
+  routeBasePath: '', // URL Route.
+  include: ['**/*.{js,jsx}'], // Extensions to include.
+};
+
+export default function pluginContentPages(
+  context: LoadContext,
+  opts: Partial<PluginOptions>,
+): Plugin<LoadedContent | null> {
+  const options = {...DEFAULT_OPTIONS, ...opts};
+  const contentPath = path.resolve(context.siteDir, options.path);
+
+  return {
+    name: 'docusaurus-plugin-content-pages',
+
+    getPathsToWatch() {
+      const {include = []} = options;
+      const globPattern = include.map(pattern => `${contentPath}/${pattern}`);
+      return [...globPattern];
+    },
+
+    async loadContent() {
+      const {include} = options;
+      const {siteConfig, siteDir} = context;
+      const pagesDir = contentPath;
+
+      if (!fs.existsSync(pagesDir)) {
+        return null;
+      }
+
+      const {baseUrl} = siteConfig;
+      const pagesFiles = await globby(include, {
+        cwd: pagesDir,
+      });
+
+      return pagesFiles.map(relativeSource => {
+        const source = path.join(pagesDir, relativeSource);
+        // Cannot use path.join() as it resolves '../' and removes the '@site'. Let webpack loader resolve it.
+        const aliasedSource = `@site/${path.relative(siteDir, source)}`;
+        const pathName = encodePath(fileToPath(relativeSource));
+        // Default Language.
+        return {
+          permalink: pathName.replace(/^\//, baseUrl || ''),
+          source: aliasedSource,
+        };
+      });
+    },
+
+    async contentLoaded({content, actions}) {
+      if (!content) {
+        return;
+      }
+
+      const {addRoute} = actions;
+
+      await Promise.all(
+        content.map(async metadataItem => {
+          const {permalink, source} = metadataItem;
+          addRoute({
+            path: permalink,
+            component: source,
+            exact: true,
+          });
+        }),
+      );
+    },
+  };
+}