use getMarkdownFromSlide function in reveal.js markdown plugin.

src/client/js/util/reveal/plugins/growi-renderer.js

@@ -2,27 +2,53 @@
  * reveal.js growi-renderer plugin.
  */
 (function() {
+  let SCRIPT_END_PLACEHOLDER = '__SCRIPT_END__';
+
+  /**
+   * Retrieves the markdown contents of a slide section
+   * element. Normalizes leading tabs/whitespace.
+   * Refered from The reveal.js markdown plugin.
+   * https://github.com/hakimel/reveal.js/blob/master/plugin/markdown/markdown.js
+   */
+  function getMarkdownFromSlide( section ) {
+    // look for a <script> or <textarea data-template> wrapper
+    let template = section.querySelector( '[data-template]' ) || section.querySelector( 'script' );
+
+    // strip leading whitespace so it isn't evaluated as code
+    let text = ( template || section ).textContent;
+
+    // restore script end tags
+    text = text.replace( new RegExp( SCRIPT_END_PLACEHOLDER, 'g' ), '</script>' );
+
+    let leadingWs = text.match( /^\n?(\s*)/ )[1].length;
+    let leadingTabs = text.match( /^\n?(\t*)/ )[1].length;
+
+    if (leadingTabs > 0) {
+      text = text.replace( new RegExp('\\n?\\t{' + leadingTabs + '}','g'), '\n' );
+    }
+    else if (leadingWs > 1) {
+      text = text.replace( new RegExp('\\n? {' + leadingWs + '}', 'g'), '\n' );
+    }
+
+    return text;
+  }
+
   /**
-   * convert data-markdown slides to HTML slides by GrowiRenderer.
+   * Converts data-markdown slides to HTML slides by GrowiRenderer.
    */
   function convertSlides() {
     let sections = document.querySelectorAll( '[data-markdown]');
     let section;
-    let template;
     let markdown;
-    let parsedHTML;
     for (let i = 0, len = sections.length; i < len; i++ ) {
       section = sections[i];
 
       // Only parse the same slide once
       if (!section.getAttribute('data-markdown-parsed')) {
-        section.setAttribute('data-markdown-parsed', true);
-        // look for a <script> or <textarea data-template> wrapper
-        template = section.querySelector('[data-template]') || section.querySelector('script');
-        markdown = template.textContent;
+        section.setAttribute('data-markdown-parsed', 'true');
+        markdown = getMarkdownFromSlide(section);
 
-        parsedHTML = growiRenderer.process(markdown);
-        section.innerHTML = parsedHTML;
+        section.innerHTML = growiRenderer.process(markdown);
       }
     }
   }
@@ -31,7 +57,7 @@
   // parent window DOM (crowi.js) of presentation window.
   let parentWindow = window.parent;
 
-  // generate GrowiRenderer instance and setup.
+  // create GrowiRenderer instance and setup.
   let growiRenderer = new GrowiRenderer(parentWindow.crowi, parentWindow.crowiRenderer, {mode: 'editor'});
   growiRenderer.setup();
   // TODO: retract code block by GrowiRenderer in GC-1354.