add filter option. closes #28.

Author: stevenschobert

src/instafeed.coffee

@@ -128,6 +128,10 @@ class Instafeed
       images = response.data
       images = images[0..@options.limit] if images.length > @options.limit
 
+      # filter the results
+      if @options.filter? and typeof @options.filter is 'function'
+        images = @_filter(images, @options.filter)
+
       # determine whether to parse a template, or use html fragments
       if @options.template? and typeof @options.template is 'string'
         # create an html string
@@ -331,6 +335,15 @@ class Instafeed
 
     return data
 
+  # helper method to filter out images
+  _filter: (images, filter) ->
+    filteredImages = []
+    for image in images
+      do (image) ->
+        filteredImages.push(image) if filter(image)
+    return filteredImages
+
+
 # set up exports
 root = exports ? window
 root.Instafeed = Instafeed

test/instafeedTest.coffee

@@ -202,8 +202,21 @@ describe 'Instafeed instace', ->
     feed._sortBy(testdata, 'meta.likes.count', true).should.deep.equal [image2, image1, image3]
     feed._sortBy(testdata, 'meta.comments', false).should.deep.equal [image2, image1, image3]
 
+  it 'should be able to filter data with a callback', ->
+    feed = new Instafeed
+
+    filterFunc = (image) ->
+      return image.name is "image1"
 
+    image1 =
+      name: "image1"
+    image2 =
+      name: "image2"
+    image3 =
+      name: "image3"
+    testdata = [image1, image2, image3]
 
+    feed._filter(testdata, filterFunc).should.deep.equal [image1]