Fix bug for list-items without children

Author: wooorm

lib/handlers/list-item.js

@@ -10,7 +10,7 @@ var all = require('../all');
 function listItem(h, node, parent) {
   var children = node.children;
   var head = children[0];
-  var single = (!parent || !parent.loose) && head.children && children.length === 1;
+  var single = (!parent || !parent.loose) && head && head.children && children.length === 1;
   var result = all(h, single ? head : node);
   var container;
   var props = {};

test/list-item.js

@@ -103,5 +103,11 @@ test('ListItem', function (t) {
     'should support checkboxes in `listItem`s without paragraph'
   );
 
+  t.deepEqual(
+    to(u('listItem', [])),
+    u('element', {tagName: 'li', properties: {}}, []),
+    'should support `listItem`s without children'
+  );
+
   t.end();
 });