add fn.parents() method

README.rdoc

@@ -48,6 +48,7 @@ Context and .find calls are equivalent:
 
   find('selector'): find all children/grandchildren that match the given selector
   closest('selector'): find the first matching element by going upwards starting from the current element
+  parents('selector'): get all ancestors of elements in collection, optionally filtered by a selector
   parent(): immediate parent node of each element in collection
   next(): next siblings
   prev(): previous siblings

src/zepto.js

@@ -76,6 +76,18 @@ var Zepto = (function() {
       while(node && node !== document && nodes.indexOf(node) < 0) node = node.parentNode;
       return $(node);
     },
+    parents: function(selector){
+      var ancestors = [], nodes = this.get();
+      while (nodes.length > 0)
+        nodes = compact(nodes.map(function(node){
+          if ((node = node.parentNode) && node !== document && ancestors.indexOf(node) < 0) {
+            ancestors.push(node);
+            return node;
+          }
+        }));
+      ancestors = $(ancestors);
+      return selector === undefined ? ancestors : ancestors.filter(selector);
+    },
     parent: function(selector){
       var node, nodes = [];
       this.each(function(el){

test/zepto.html

@@ -345,6 +345,20 @@ <h1>Zepto DOM unit tests</h1>
         t.assertLength(0, el.closest('div'));
       },
 
+      testParents: function(t){
+        var body = document.body, html = body.parentNode, container = $('#parents');
+        t.assertEqualCollection($([body, html]), container.parents());
+
+        var expected = $('#li1 > ul').get();
+        expected.push($('#li1').get(0));
+        expected.push(container.get(0));
+        expected = expected.concat([body, html]);
+        t.assertEqualCollection($(expected), $('#li1').find('li').parents());
+
+        expected = [$('#nested').get(0), $('#parents').get(0)];
+        t.assertEqualCollection($(expected), $('#li2').parents('ul'));
+      },
+
       testParent: function(t){
         var el = $('#li1');
         t.assertEqualCollection($('#parents'), el.parent());