add :empty

Author: eush77

README.md

@@ -71,7 +71,7 @@ That's it!
   - [ ] `:last-of-type`
   - [x] `:only-child`
   - [ ] `:only-of-type`
-  - [ ] `:empty`
+  - [x] `:empty`
 - [x] Negation pseudo-class: `*:not(paragraph)`
 
 ## API

lib/match-node.js

@@ -79,6 +79,9 @@ function matchPseudos (rule, node, nodeIndex, parent) {
       case 'only-child':
         return parent && parent.children.length == 1;
 
+      case 'empty':
+        return node.children && !node.children.length;
+
       case 'not':
         return !matchNode(pseudo.value.rule, node, nodeIndex, parent);
 

test/select.js

@@ -205,6 +205,14 @@ test('structural pseudo-classes', function (t) {
     t.end();
   });
 
+  t.test(':empty', function (t) {
+    t.deepEqual(select(ast, ':root:empty'), []);
+    t.deepEqual(select(ast, 'text:empty'), []);
+    t.deepEqual(select(ast, 'list:not(:empty)'), select(ast, 'list'));
+    t.deepEqual(select(ast, ':empty'), select(ast, 'div > div'));
+    t.end();
+  });
+
   t.end();
 });