Merge pull request cheeriojs#527 from jugglinmike/add-back

Implement `$.prototype.addBack`

Readme.md

@@ -505,6 +505,15 @@ $('.apple').add('.orange').length
 //=> 2
 ```
 
+#### .addBack( [filter] )
+
+Add the previous set of elements on the stack to the current set, optionally filtered by a selector.
+
+```js
+$('li').eq(0).addBack('.orange').length
+//=> 2
+```
+
 ### Manipulation
 Methods for modifying the DOM structure.
 

lib/api/traversing.js

@@ -403,3 +403,11 @@ exports.add = function(other, context) {
 
   return selection;
 };
+
+// Add the previous set of elements on the stack to the current set, optionally
+// filtered by a selector.
+var addBack = exports.addBack = function(selector) {
+  return this.add(
+    arguments.length ? this.prevObject.filter(selector) : this.prevObject
+  );
+};

test/api.traversing.js

@@ -1275,4 +1275,48 @@ describe('$(...)', function() {
     });
   });
 
+  describe('.addBack', function() {
+    describe('() : ', function() {
+      it('includes siblings and self', function() {
+        var $selection = $('.orange').siblings().addBack();
+
+        expect($selection).to.have.length(3);
+        expect($selection[0]).to.be($('.apple')[0]);
+        expect($selection[1]).to.be($('.orange')[0]);
+        expect($selection[2]).to.be($('.pear')[0]);
+      });
+      it('includes children and self', function() {
+        var $selection = $('#fruits').children().addBack();
+
+        expect($selection).to.have.length(4);
+        expect($selection[0]).to.be($('#fruits')[0]);
+        expect($selection[1]).to.be($('.apple')[0]);
+        expect($selection[2]).to.be($('.orange')[0]);
+        expect($selection[3]).to.be($('.pear')[0]);
+      });
+      it('includes parent and self', function() {
+        var $selection = $('.apple').parent().addBack();
+
+        expect($selection).to.have.length(2);
+        expect($selection[0]).to.be($('#fruits')[0]);
+        expect($selection[1]).to.be($('.apple')[0]);
+      });
+      it('includes parents and self', function() {
+        var $ = cheerio.load(food);
+        var $selection = $('.apple').parents().addBack();
+
+        expect($selection).to.have.length(3);
+        expect($selection[0]).to.be($('#food')[0]);
+        expect($selection[1]).to.be($('#fruits')[0]);
+        expect($selection[2]).to.be($('.apple')[0]);
+      });
+    });
+    it('(filter) : filters the previous selection', function() {
+      var $selection = $('li').eq(1).addBack('.apple');
+
+      expect($selection).to.have.length(2);
+      expect($selection[0]).to.be($('.apple')[0]);
+      expect($selection[1]).to.be($('.orange')[0]);
+    });
+  });
 });