Allow accessible scope exclusion for blank value

lib/periscope.rb

@@ -26,13 +26,26 @@ def periscope_call(chain, scope, param)
     method = periscope_method(scope, options)
     values = periscope_values(param, options)
 
-    if options[:boolean]
-      values.first ? chain.send(method) : chain
+    if periscope_ignore?(values.first, options)
+      chain
     else
-      chain.send(method, *values)
+      options[:boolean] ? chain.send(method) : chain.send(method, *values)
     end
   end
 
+  def periscope_ignore?(value, options)
+    if options[:ignore_blank]
+      periscope_blank?(value)
+    elsif options[:boolean]
+      !value
+    end
+  end
+
+  def periscope_blank?(value)
+    return true unless value
+    value.respond_to?(:blank?) ? value.blank? : value.empty?
+  end
+
   def periscope_method(scope, options)
     options[:method] || [options[:prefix], scope, options[:suffix]].compact.join
   end

spec/shared/periscopic.rb

@@ -117,6 +117,36 @@ def expect_scopes(calls)
       model.periscope(foo: "bar")
     end
 
+    it "allows accessible scope exclusion given a blank param" do
+      model.should_not_receive(:foo)
+      model.scope_accessible(:foo, ignore_blank: true)
+      model.periscope(foo: nil)
+      model.periscope(foo: "")
+      model.periscope(foo: [])
+      model.periscope(foo: {})
+    end
+
+    it "calls accessible scopes with values when ignoring blank params" do
+      expect_scopes(foo: ["bar"])
+      model.scope_accessible(:foo, ignore_blank: true)
+      model.periscope(foo: "bar")
+    end
+
+    it "allows accessible boolean scope exclusion given a blank param" do
+      model.should_not_receive(:foo)
+      model.scope_accessible(:foo, boolean: true, ignore_blank: true)
+      model.periscope(foo: nil)
+      model.periscope(foo: "")
+      model.periscope(foo: [])
+      model.periscope(foo: {})
+    end
+
+    it "calls accessible boolean scopes when ignoring blank params" do
+      expect_scopes(foo: [])
+      model.scope_accessible(:foo, boolean: true, ignore_blank: true)
+      model.periscope(foo: "bar")
+    end
+
     it "passes along a nil param" do
       expect_scopes(foo: [nil])
       model.scope_accessible(:foo)