As the title says, the behavior of react-dates is very bad with a large number (~500) of blocked dates.

Code of whole application is here: https://github.com/milanpanin/react-dates/blob/master/src/App.js Also, app is live here: https://react-dates-test.netlify.app/ and here you can see how slow the application actually works 😕

// [disableNext3, disableBetween, disableNext6Between] - represent arrays with all together about 500 dates
  const isBlocked = (day) => ([disableNext3, disableBetween, disableNext6Between].flat()).some(date => day.isSame(date, 'day'));

  return ( 
    <div className="App">
        <DateRangePicker
          startDateId="startDate"
          endDateId="endDate"
          startDate={startDate}
          endDate={endDate}
          onDatesChange={({ startDate, endDate }) => { setStartDate( startDate ), setEndDate( endDate )}}
          focusedInput={focusedInput}
          onFocusChange={(focusedInput) => { setSocusedInput( focusedInput )}}
          isDayBlocked={isBlocked}
        />
        ...

I also tried to implement a spinner on each render, but without success. Is there any solution to my problem?