add :last-child

Author: eush77

README.md

@@ -66,7 +66,7 @@ That's it!
   - [ ] `:nth-of-type(2n+1)`
   - [ ] `:nth-last-of-type(2n+1)`
   - [x] `:first-child`
-  - [ ] `:last-child`
+  - [x] `:last-child`
   - [ ] `:first-of-type`
   - [ ] `:last-of-type`
   - [ ] `:only-child`

lib/match-node.js

@@ -68,7 +68,10 @@ function matchPseudos (rule, node, nodeIndex, parent) {
         return pseudo.value(nodeIndex);
 
       case 'first-child':
-        return nodeIndex == 0;
+        return !parent || nodeIndex == 0;
+
+      case 'last-child':
+        return !parent || nodeIndex == parent.children.length - 1;
 
       case 'not':
         return !matchNode(pseudo.value.rule, node, nodeIndex, parent);

test/select.js

@@ -166,6 +166,14 @@ test('structural pseudo-classes', function (t) {
     t.end();
   });
 
+  t.test(':last-child', function (t) {
+    t.deepEqual(select(ast, ':root:last-child'), [ast]);
+    t.deepEqual(select(ast, 'tableCell:last-child *')
+                .map(function (node) { return node.value }),
+                ['mi', 'dolor', '15000']);
+    t.end();
+  });
+
   t.end();
 });