Fix array boundage end by array.lenth-1

lib/json-compare/comparer.rb

@@ -57,18 +57,30 @@ def compare_arrays(old_array, new_array)
 
       result = get_diffs_struct
 
-      (0..inters).map do |n|
+      (1..inters).map do |n|
+        res = compare_elements(old_array[-n], new_array[-n])
+        if res.nil? || (res.respond_to?(:empty?) && res.empty?)
+          old_array_length -= 1
+          new_array_length -= 1
+        else
+          break
+        end
+      end
+
+      inters = [old_array_length, new_array_length].min
+
+      (0..(inters - 1)).map do |n|
         res = compare_elements(old_array[n], new_array[n])
         result[:update][n] = res unless (res.nil? || (res.respond_to?(:empty?) && res.empty?))
       end
 
       # the rest of the larger array
       if inters == old_array_length
-        (inters..new_array_length).each do |n|
+        (inters..(new_array_length - 1)).each do |n|
           result[:append][n] = new_array[n]
         end
       else
-        (inters..old_array_length).each do |n|
+        (inters..(old_array_length - 1)).each do |n|
           result[:remove][n] = old_array[n]
         end
       end

spec/lib/json-compare_spec.rb

@@ -128,8 +128,18 @@
     end
 
     it "should compare arrays of fixnums" do
-      result =  JsonCompare.get_diff([1, 2, 3], [1, 2, 3, 4])
-      result.should eq(:append => { 3 => 4 }, :update => { 3 => 4 })
+      result =  JsonCompare.get_diff([1, 2, 3], [1, 2, 3, 4, 5])
+      result.should eq(:append => { 3 => 4, 4 => 5 })
+    end
+
+    it "should compare arrays of remove last element" do
+      result =  JsonCompare.get_diff([1, 2, 3, 4, 5], [1, 2, 3])
+      result.should eq(:remove => { 3 => 4, 4 => 5 })
+    end
+
+    it "should compare arrays of remove hash" do
+      result =  JsonCompare.get_diff([{"a"=>1}, {"a"=>2}, {"a"=>3}, {"a"=>4}, {"a"=>5}], [{"a"=>1}, {"a"=>2}, {"a"=>3}, {"a"=>5}])
+      result.should eq(:remove => { 3 => {"a"=>4} })
     end
   end