Fix for key_format! to handle nested hashes

lib/jbuilder.rb

@@ -43,11 +43,11 @@ def set!(key, value = BLANK, *args, &block)
         # json.age 32
         # json.person another_jbuilder
         # { "age": 32, "person": { ...  }
-        value.attributes!
+        _format_keys(value.attributes!)
       else
         # json.age 32
         # { "age": 32 }
-        value
+        _format_keys(value)
       end
     elsif _is_collection?(value)
       # json.comments @post.comments, :content, :created_at
@@ -272,11 +272,11 @@ def _merge_values(current_value, updates)
     if _blank?(updates)
       current_value
     elsif _blank?(current_value) || updates.nil? || current_value.empty? && ::Array === updates
-      updates
+      _format_keys(updates)
     elsif ::Array === current_value && ::Array === updates
-      current_value + updates
+      current_value + _format_keys(updates)
     elsif ::Hash === current_value && ::Hash === updates
-      current_value.deep_merge(updates)
+      current_value.deep_merge(_format_keys(updates))
     else
       raise MergeError.build(current_value, updates)
     end
@@ -286,6 +286,16 @@ def _key(key)
     @key_formatter ? @key_formatter.format(key) : key.to_s
   end
 
+  def _format_keys(hash_or_array)
+    if ::Array === hash_or_array
+      hash_or_array.map { |value| _format_keys(value) }
+    elsif ::Hash === hash_or_array
+      ::Hash[hash_or_array.collect { |k, v| [_key(k), _format_keys(v)] }]
+    else
+      hash_or_array
+    end
+  end
+
   def _set_value(key, value)
     raise NullError.build(key) if @attributes.nil?
     raise ArrayError.build(key) if ::Array === @attributes

test/jbuilder_test.rb

@@ -581,6 +581,58 @@ class JbuilderTest < ActiveSupport::TestCase
     assert_equal ['oats and friends'], result.keys
   end
 
+  test 'key_format! with merge!' do
+    hash = { camel_style: 'for JS' }
+    result = jbuild do |json|
+      json.key_format! camelize: :lower
+      json.merge! hash
+    end
+
+    assert_equal ['camelStyle'], result.keys
+  end
+
+  test 'key_format! with merge! deep' do
+    hash = { camel_style: { sub_attr: 'for JS' } }
+    result = jbuild do |json|
+      json.key_format! camelize: :lower
+      json.merge! hash
+    end
+
+    assert_equal ['subAttr'], result['camelStyle'].keys
+  end
+
+  test 'key_format! with set! array of hashes' do
+    names = [{ first_name: 'camel', last_name: 'case' }]
+    result = jbuild do |json|
+      json.key_format! camelize: :lower
+      json.set! :names, names
+    end
+
+    assert_equal %w[firstName lastName], result['names'][0].keys
+  end
+
+  test 'key_format! with array! of hashes' do
+    names = [{ first_name: 'camel', last_name: 'case' }]
+    result = jbuild do |json|
+      json.key_format! camelize: :lower
+      json.array! names
+    end
+
+    assert_equal %w[firstName lastName], result[0].keys
+  end
+
+  test 'key_format! with merge! array of hashes' do
+    names = [{ first_name: 'camel', last_name: 'case' }]
+    new_names = [{ first_name: 'snake', last_name: 'case' }]
+    result = jbuild do |json|
+      json.key_format! camelize: :lower
+      json.array! names
+      json.merge! new_names
+    end
+
+    assert_equal %w[firstName lastName], result[1].keys
+  end
+
   test 'default key_format!' do
     Jbuilder.key_format camelize: :lower
     result = jbuild{ |json| json.camel_style 'for JS' }