message: wip(ssr): not add css class if there is no property can animate.
diff: @@ -5,7 +5,7 @@ import Path from '../graphic/Path';
  import SVGPathRebuilder from './SVGPathRebuilder';
  import PathProxy from '../core/PathProxy';
  import { getPathPrecision, getSRTTransformString } from './helper';
  -import { each, extend, isString, keys } from '../core/util';
  +import { each, extend, isEmptyObject, isString, keys } from '../core/util';
  import Animator from '../animation/Animator';
  import { CompoundPath } from '../export';
  @@ -287,7 +287,7 @@ export function createCSSAnimation(
  }
  const percents = keys(finalKfs);
  - if (percents.length) {
  + if (percents.length && !isEmptyObject(finalKfs[percents[0]])) {
  const animationName = addAnimation(finalKfs, scope);
  // eslint-disable-next-line
  for (let attrName in finalKfs[percents[0]]) {
  