Add mermaid support

browser/components/MarkdownPreview.js

@@ -7,6 +7,7 @@ import 'codemirror-mode-elixir'
 import consts from 'browser/lib/consts'
 import Raphael from 'raphael'
 import flowchart from 'flowchart'
+import mermaidRender from './render/MermaidRender'
 import SequenceDiagram from 'js-sequence-diagrams'
 import eventEmitter from 'browser/main/lib/eventEmitter'
 import htmlTextHelper from 'browser/lib/htmlTextHelper'
@@ -496,6 +497,10 @@ export default class MarkdownPreview extends React.Component {
         el.innerHTML = 'Sequence diagram parse error: ' + e.message
       }
     })
+
+    _.forEach(this.refs.root.contentWindow.document.querySelectorAll('.mermaid'), (el) => {
+      mermaidRender(el, htmlTextHelper.decodeEntities(el.innerHTML))
+    })
   }
 
   focus () {

browser/components/render/MermaidRender.js

@@ -0,0 +1,28 @@
+import mermaidAPI from 'mermaid'
+
+function getRandomInt (min, max) {
+  return Math.floor(Math.random() * (max - min)) + min
+}
+
+function getId () {
+  var pool = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
+  var id = 'm-'
+  for (var i = 0; i < 7; i++) {
+    id += pool[getRandomInt(0, 16)]
+  }
+  return id
+}
+
+function render (element, content) {
+  try {
+    mermaidAPI.render(getId(), content, (svgGraph) => {
+      element.innerHTML = svgGraph
+    })
+  } catch (e) {
+    console.error(e)
+    element.className = 'mermaid-error'
+    element.innerHTML = 'mermaid diagram parse error: ' + e.message
+  }
+}
+
+export default render

browser/lib/markdown.js

@@ -40,6 +40,9 @@ class Markdown {
         if (langType === 'sequence') {
           return `<pre class="sequence">${str}</pre>`
         }
+        if (langType === 'mermaid') {
+          return `<pre class="mermaid">${str}</pre>`
+        }
         return '<pre class="code CodeMirror">' +
           '<span class="filename">' + fileName + '</span>' +
           createGutter(str, firstLineNumber) +