observe(o = {}, callback) {
      var _$observers;

      let options = Object.assign({
        element: this.element
      }, o);
      return (_$observers = _.observers) === null || _$observers === void 0 ? void 0 : _$observers.observe(options, callback);
    }
Mavo: Create web applications by writing HTML and CSS!
@author Lea Verou and contributors
@version v0.3.1