Code review suggestions from akihikodaki

Also fixed a syntax error in tests for AccountInteractions.

app/javascript/mastodon/reducers/mutes.js

@@ -22,7 +22,7 @@ export default function mutes(state = initialState, action) {
       state.setIn(['new', 'notifications'], true);
     });
   case MUTES_TOGGLE_HIDE_NOTIFICATIONS:
-    return state.setIn(['new', 'notifications'], !state.getIn(['new', 'notifications']));
+    return state.updateIn(['new', 'notifications'], (old) => !old);
   default:
     return state;
   }

app/models/concerns/account_interactions.rb

@@ -79,8 +79,7 @@ module AccountInteractions
     mute = mute_relationships.create_with(hide_notifications: notifications).find_or_create_by!(target_account: other_account)
     # When toggling a mute between hiding and allowing notifications, the mute will already exist, so the find_or_create_by! call will return the existing Mute without updating the hide_notifications attribute. Therefore, we check that hide_notifications? is what we want and set it if it isn't.
     if mute.hide_notifications? != notifications
-      mute.hide_notifications = notifications
-      mute.save!
+      mute.update!(hide_notifications: notifications)
     end
   end
 

db/migrate/20170716191202_add_hide_notifications_to_mute.rb

@@ -1,5 +1,5 @@
 class AddHideNotificationsToMute < ActiveRecord::Migration[5.1]
   def change
-    add_column :mutes, :hide_notifications, :boolean, default: false, null: false
+    add_column :mutes, :hide_notifications, :boolean, default: true, null: false
   end
 end

spec/controllers/api/v2/mutes_controller_spec.rb

@@ -16,7 +16,7 @@ RSpec.describe Api::V2::MutesController, type: :controller do
       get :index, params: { limit: 1 }
     end
 
-    let(:mutes) { JSON.parse(response.body) }
+    let(:mutes) { body_as_json }
 
     it 'returns http success' do
       expect(response).to have_http_status(:success)
@@ -27,7 +27,7 @@ RSpec.describe Api::V2::MutesController, type: :controller do
     end
 
     it 'returns whether the mute hides notifications' do
-      expect(mutes.first["hide_notifications"]).to be false
+      expect(mutes.first[:hide_notifications]).to be false
     end 
   end
 end

spec/models/concerns/account_interactions_spec.rb

@@ -4,7 +4,6 @@ describe AccountInteractions do
   describe 'muting an account' do
     let(:me) { Fabricate(:account, username: 'Me') }
     let(:you) { Fabricate(:account, username: 'You') }
-    end
 
     context 'with the notifications option unspecified' do
       before do