Custom Modifiers

In DayPicker, a custom modifier is added to a day when the day matches a specific condition, called Matcher.

Modifiers are set using the modifiers prop. When matching a date, modifiers are passed to the onSelect event and to other DayEventHandler (onDayClick etc.) to inspect the days the user has interacted with.

For example, you can use a custom modifier to mark days as already booked in a booking app.

<DayPicker
  modifiers={{
    booked: [
      new Date(2022, 5, 8),
      new Date(2022, 5, 9),
      new Date(2022, 5, 10),
      { from: new Date(2022, 5, 15), to: new Date(2022, 5, 20) }
    ]
  }}
  onDayClick={(date, modifiers) => {
    if (modifiers.booked) {
      alert("This day is already booked.");
    }
  }}
/>

Understanding Modifiers

Use modifiers to change the appearance of the days in the calendar or to inspect the days the user has interacted with (e.g. picking a day)
DayPicker comes with some pre-built modifiers, such as disabled, selected, hidden, today, range_start, etc. designed to cover the most common use cases.
It is possible to implement custom modifiers, extending the behavior of DayPicker: see Custom Modifiers below for more details.

Built-in Modifiers

`selected` Modifier

<DayPicker selected={new Date()} />

When in selection mode, use the selected prop to add the selected modifier to the selected dates, and style them accordingly. To see how to implement the selected modifier, see the Selecting days guide.

`disabled` Modifier

Use the disabled modifier to disable one or more days. Pass a Matcher or an array of Matchers to choose the disabled days:

// Disable Sundays and Saturdays
<DayPicker mode="range" disabled={{ dayOfWeek: [0, 6] }} />

September 2024

`hidden` Modifier

The hidden modifier removes the day from the calendar. Set the hidden days using the hidden prop.

const hiddenDays = [
  new Date(2022, 5, 10),
  new Date(2022, 5, 20),
  new Date(2022, 5, 11)
];

<DayPicker defaultMonth={hiddenDays[0]} hidden={hiddenDays} />;

June 2022

Su	Mo	Tu	We	Th	Fr	Sa
29	30	31	1	2	3	4
5	6	7	8	9	10	11
12	13	14	15	16	17	18
19	20	21	22	23	24	25
26	27	28	29	30	1	2

`today` Modifier

The today modifier is a special modifier added to the current date. You can also change the current date using the today prop.

function Example() {
  const handleDayClick: DayMouseEventHandler = (day, modifiers) => {
    if (modifiers.today) {
      alert("You clicked the today’s date.");
    }
  };
  return (
    <DayPicker onDayClick={handleDayClick} today={new Date(2019, 12, 22)} />
  );
}

September 2024

Styling Modifiers

A day can be styled according to its modifiers – using CSS or inline styles. See Styling DayPicker for more details.

const bookedDays = [
  new Date(2021, 5, 8),
  new Date(2021, 5, 9),
  new Date(2021, 5, 11)
];
export function ModifiersWithClassnames() {
  return (
    <DayPicker
      defaultMonth={bookedDays[0]}
      modifiers={{
        booked: bookedDays
      }}
      modifiersClassNames={{
        booked: "my-booked-class"
      }}
    />
  );
}

Add the my-booked-class class to your CSS:

.my-booked-class {
  background-color: tomato;
  color: white;
  border-radius: 50%;
}

June 2021

Understanding Modifiers​

Built-in Modifiers​

selected Modifier​

disabled Modifier​

hidden Modifier​

today Modifier​

Styling Modifiers​