How to use the core-js/library/fn/set function in core-js

.then(() => {
        const reduxState = escape(JSON.stringify(getState()));
        const css = new Set();
        /* eslint-disable no-underscore-dangle */
        const html = ReactDOMServer.renderToString(
           { css.add(styles._getCss()); }}>
            
              { }
            
          
        );
        const head = Helmet.rewind();
        res.render('index', {
          html,
          reduxState,
          inlineCss: arrayFrom(css).join(''),
          head,
          isMobile,
        });

}).then(({ redialMap, redialProps }) => {
      const reduxState = escape(JSON.stringify(getState()));
      const css = new Set();
      /* eslint-disable no-underscore-dangle */
      let html;
      const component = applyRouterMiddleware(useRedial({ redialMap }))(renderProps);

      try {
        html = ReactDOMServer.renderToString(
          
             styles._getCss && css.add(styles._getCss())}
            >
              
                { component }
              
            
          
        );

function _flush(rootNode: AnimatedValue): void {
  var animatedStyles = new Set();
  function findAnimatedStyles(node) {
    if (typeof node.update === 'function') {
      animatedStyles.add(node);
    } else {
      node.__getChildren().forEach(findAnimatedStyles);
    }
  }
  findAnimatedStyles(rootNode);
  animatedStyles.forEach(animatedStyle => animatedStyle.update());
}

function setupRegistrySlot(auctionId) {
    registry[auctionId] = {};
    registry[auctionId].bidStorage = new Set();
    registry[auctionId].queueDispatcher = createDispatcher(queueTimeDelay);
    registry[auctionId].initialCacheKey = utils.generateUUID();
  }