code: function getModifiedProperties(entity, componentName) {
      var data = entity.components[componentName].data;
      var defaultData = entity.components[componentName].schema;
      var diff = {};
      for (var key in data) {
        // Prevent adding unknown attributes
        if (!defaultData[key]) {
          continue;
        }
  
        var defaultValue = defaultData[key].default;
        var currentValue = data[key];
  
        // Some parameters could be null and '' like mergeTo
        if ((currentValue || defaultValue) && currentValue !== defaultValue) {
          diff[key] = data[key];
        }
      }
      return diff;
    }
docs: Get the list of modified properties
  @param  {Element} entity        Entity where the component belongs
  @param  {string} componentName Component name
  @return {object}               List of modified properties with their value