Handling edge case with empty metadata - fixes jdan#55

examples/empty.md

@@ -0,0 +1,5 @@
+--
+
+### Unidentified Flying Slideshow
+
+This slideshow contains no metadata!

lib/cleaver.js

@@ -56,7 +56,7 @@ Cleaver.prototype._loadDocument = function () {
 Cleaver.prototype._renderSlides = function () {
   var self = this;
   var slices = this._slice(self.external.loaded.document);
-  this.metadata = yaml.safeLoad(slices[0]);
+  this.metadata = yaml.safeLoad(slices[0]) || {};
 
   for (var i = 1; i < slices.length; i++)
     this.slides.push(md(slices[i]));
@@ -194,6 +194,19 @@ Cleaver.prototype._slice = function(document) {
   var slices = [];
 
   for (var i = 0; i < cuts.length; i++) {
+
+    /**
+     * EDGE CASE
+     * If the slideshow begins with `--`, that is, the metadata is empty and
+     * the user did *not* include a blank line at the top, we will insert an
+     * empty slide at the beginning (to represent empty metadata), followed
+     * by the first slice (with the -- chopped off).
+     */
+    if (i == 0 && cuts[i].match(/^--/)) {
+      slices.push("");
+      cuts[i] = cuts[i].slice(2);
+    }
+
     slices.push(cuts[i].trim());
   }