code: function doSetAttribute(el, props, propName) {
    if (propName === 'className') {
      el.setAttribute('class', props.className);
    } else if (props[propName] && props[propName].constructor === Function) {
      return;
    } else {
      el.setAttribute(propName, props[propName]);
    }
  }
docs: Call `.setAttribute()` on the `ref`, passing prop data directly to A-Frame.