old_contents: export default (entityData = []) => (_, entity) => {
      const newId =
          entityData.length > 0 ? entityData[entityData.length - 1].id + 1 : 1;
      const newEntity = Object.assign(entity, { id: newId });
      entityData.push(newEntity);
      return newEntity;
  };
  
new_contents: export default (entityData = []) => (_, entity) => {
      const newId =
          entityData.length > 0 ? entityData[entityData.length - 1].id + 1 : 0;
      const newEntity = Object.assign(entity, { id: newId });
      entityData.push(newEntity);
      return newEntity;
  };
  
subject: Create create.js