feature(markdown): add markdown api

Closes #325

Author: knsh14

lib/GitHub.js

@@ -12,6 +12,7 @@ import Search from './Search';
 import RateLimit from './RateLimit';
 import Repository from './Repository';
 import Organization from './Organization';
+import Markdown from './Markdown';
 
 /**
  * GitHub encapsulates the functionality to create various API wrapper objects.
@@ -93,6 +94,14 @@ class GitHub {
       return new RateLimit(this.__auth, this.__apiBase);
    }
 
+   /**
+    * Create a new Markdown wrapper
+    * @return {Markdown}
+    */
+   getMarkdown() {
+       return new Markdown(this.__auth, this.__apiBase);
+   }
+
    _getFullName(user, repo) {
       let fullname = user;
 

lib/Markdown.js

@@ -0,0 +1,39 @@
+/**
+ * @file
+ * @copyright  2013 Michael Aufreiter (Development Seed) and 2016 Yahoo Inc.
+ * @license    Licensed under {@link https://spdx.org/licenses/BSD-3-Clause-Clear.html BSD-3-Clause-Clear}.
+ *             Github.js is freely distributable.
+ */
+
+import Requestable from './Requestable';
+
+/**
+ * RateLimit allows users to query their rate-limit status
+ */
+class Markdown extends Requestable {
+   /**
+    * construct a RateLimit
+    * @param {Requestable.auth} auth - the credentials to authenticate to GitHub
+    * @param {string} [apiBase] - the base Github API URL
+    * @return {Promise} - the promise for the http request
+    */
+   constructor(auth, apiBase) {
+      super(auth, apiBase);
+   }
+
+   /**
+    * Render html from Markdown text.
+    * @see https://developer.github.com/v3/markdown/#render-an-arbitrary-markdown-document
+    * @param {Object} options
+    * @param {string} [options.text] - the markdown text to convert
+    * @param {string} [options.mode=markdown] - can be either `markdown` or `gfm`
+    * @param {string} [options.context] - repository name if mode is gfm
+    * @param {Requestable.callback} [cb] - will receive the converted html
+    * @return {Promise} - the promise for the http request
+    */
+   render(options, cb) {
+      return this._request('POST', '/markdown', options, cb);
+   }
+}
+
+module.exports = Markdown;

test/markdown.spec.js

@@ -0,0 +1,44 @@
+import expect from 'must';
+
+import Github from '../lib/GitHub';
+import testUser from './fixtures/user.json';
+
+describe('Markdown', function() {
+   let github;
+   let markdown;
+
+   before(function() {
+      github = new Github({
+         username: testUser.USERNAME,
+         password: testUser.PASSWORD,
+         auth: 'basic'
+      });
+
+      markdown = github.getMarkdown();
+   });
+
+   it('should convert markdown to html as plain Markdown', function(done) {
+      const options = {
+         text: 'Hello world github/linguist#1 **cool**, and #1!'
+      };
+
+      markdown.render(options)
+         .then(function({data: html}) {
+            expect(html).to.be('<p>Hello world github/linguist#1 <strong>cool</strong>, and #1!</p>\n');
+            done();
+         }).catch(done);
+   });
+
+   it('should convert markdown to html as GFM', function(done) {
+      const options = {
+         text: 'Hello world github/linguist#1 **cool**, and #1!',
+         mode: 'gfm',
+         context: 'github/gollum'
+      };
+      markdown.render(options)
+         .then(function({data: html}) {
+            expect(html).to.be('<p>Hello world <a href="https://github.com/github/linguist/issues/1" class="issue-link js-issue-link" data-url="https://github.com/github/linguist/issues/1" data-id="1012654" data-error-text="Failed to load issue title" data-permission-text="Issue title is private">github/linguist#1</a> <strong>cool</strong>, and <a href="https://github.com/gollum/gollum/issues/1" class="issue-link js-issue-link" data-url="https://github.com/gollum/gollum/issues/1" data-id="183433" data-error-text="Failed to load issue title" data-permission-text="Issue title is private">#1</a>!</p>'); // jscs:ignore
+            done();
+         }).catch(done);
+   });
+});