JSFiddle - React, Tailwind, and code Playground

JavaScript

var holidayArray2013 = [new Date('October 3, 2013 00:00:00 GMT+0200'), new Date('December 25, 2013 00:00:00 GMT+0100'), new Date('December 26, 2013 00:00:00 GMT+0100')];
var DateOfOrder = new Date('October 3, 2013 00:00:00 GMT+0200');

var isHoliday = false;
for(var i=0;i<holidayArray2013.length;i++){
    if(holidayArray2013[i].getTime() == DateOfOrder.getTime()){
        isHoliday = true;
        break;
    }
}
if (isHoliday) {
  console.log("is holiday");
}
else{
    console.log("is not holiday")
}