前台生成uuid

 generateUUID() {
        let d = new Date().getTime();
        if (window.performance && typeof window.performance.now === "function") {
          d += performance.now(); //use high-precision timer if available
        }
        let uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
          let r = (d + Math.random() * 16) % 16 | 0;
          d = Math.floor(d / 16);
          return (c == 'x' ? r : (r & 0x3 | 0x8)).toString(16);
        });
        uuid = uuid.replace(/-/g, '');
        return uuid;
      },