Refactor + add more tests (Part 2) (#854)

* Refactor doc in server.js & generate.js

* Refactor finding metadata with find() & avoid param reassign

* Refactor replacing markdown link to html + add test

* Minify func to getFile & add test

* use ./ for md link as well

* nits & better test

* better mdToHtmlify

* babel-register on versions & write-translations to transpile ES6 in server/env.js

* better docs test & move out metadata to fixtures

* Update .babelrc

lib/server/docs.js

@@ -0,0 +1,100 @@
+/**
+ * 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.
+ */
+const CWD = process.cwd();
+const siteConfig = require(`${CWD}/siteConfig.js`);
+const {join} = require('path');
+const fs = require('fs-extra');
+const React = require('react');
+const env = require('./env.js');
+const readMetadata = require('./readMetadata.js');
+const {insertTOC} = require('../core/toc.js');
+const {getPath} = require('../core/utils.js');
+
+function getFile(metadata) {
+  if (!metadata) {
+    return null;
+  }
+  let file;
+  if (env.versioning.enabled && metadata.original_id) {
+    if (env.translation.enabled && metadata.language !== 'en') {
+      file = join(CWD, 'translated_docs', metadata.language, metadata.source);
+    } else {
+      file = join(CWD, 'versioned_docs', metadata.source);
+    }
+  } else if (env.translation.enabled && metadata.language !== 'en') {
+    file = join(CWD, 'translated_docs', metadata.language, metadata.source);
+  } else {
+    file = join(CWD, '..', readMetadata.getDocsPath(), metadata.source);
+  }
+  if (!fs.existsSync(file)) {
+    return null;
+  }
+  return fs.readFileSync(file, 'utf8');
+}
+
+function mdToHtmlify(oldContent, mdToHtml, metadata) {
+  let content = oldContent;
+  const mdLinks = [];
+
+  // find any links to markdown files
+  const regex = /(?:\]\()(?:\.\/)?([^'")\]\s>]+\.md)/g;
+  let match = regex.exec(content);
+  while (match !== null) {
+    mdLinks.push(match[1]);
+    match = regex.exec(content);
+  }
+
+  // replace to their website html links
+  new Set(mdLinks).forEach(mdLink => {
+    let htmlLink = mdToHtml[mdLink];
+    if (htmlLink) {
+      htmlLink = getPath(htmlLink, siteConfig.cleanUrl);
+      htmlLink = htmlLink.replace('/en/', `/${metadata.language}/`);
+      htmlLink = htmlLink.replace(
+        '/VERSION/',
+        metadata.version && metadata.version !== env.versioning.defaultVersion
+          ? `/${metadata.version}/`
+          : '/'
+      );
+      content = content.replace(
+        new RegExp(`\\]\\((\\./)?${mdLink}`, 'g'),
+        `](${htmlLink}`
+      );
+    }
+  });
+  return content;
+}
+
+function getComponent(rawContent, mdToHtml, metadata) {
+  // generate table of contents
+  let content = insertTOC(rawContent);
+
+  // replace any links to markdown files to their website html links
+  content = mdToHtmlify(content, mdToHtml, metadata);
+
+  // replace any relative links to static assets to absolute links
+  content = content.replace(
+    /\]\(assets\//g,
+    `](${siteConfig.baseUrl}docs/assets/`
+  );
+
+  const DocsLayout = require('../core/DocsLayout.js');
+  return (
+    <DocsLayout
+      metadata={metadata}
+      language={metadata.language}
+      config={siteConfig}>
+      {content}
+    </DocsLayout>
+  );
+}
+
+module.exports = {
+  getComponent,
+  getFile,
+  mdToHtmlify,
+};