react-day-picker
Version:
Customizable Date Picker for React
90 lines (83 loc) • 2.81 kB
text/typescript
import { DayFlag } from "../UI.js";
import type { CalendarDay } from "../classes/index.js";
import type { Modifiers } from "../types/index.js";
enum FocusTargetPriority {
Today = 0,
Selected,
LastFocused,
FocusedModifier
}
/**
* Determines if a day is focusable based on its modifiers.
*
* A day is considered focusable if it is not disabled, hidden, or outside the
* displayed month.
*
* @param modifiers The modifiers applied to the day.
* @returns `true` if the day is focusable, otherwise `false`.
*/
function isFocusableDay(modifiers: Modifiers) {
return (
!modifiers[DayFlag.disabled] &&
!modifiers[DayFlag.hidden] &&
!modifiers[DayFlag.outside]
);
}
/**
* Calculates the focus target day based on priority.
*
* This function determines the day that should receive focus in the calendar,
* prioritizing days with specific modifiers (e.g., "focused", "today") or
* selection states.
*
* @param days The array of `CalendarDay` objects to evaluate.
* @param getModifiers A function to retrieve the modifiers for a given day.
* @param isSelected A function to determine if a day is selected.
* @param lastFocused The last focused day, if any.
* @returns The `CalendarDay` that should receive focus, or `undefined` if no
* focusable day is found.
*/
export function calculateFocusTarget(
days: CalendarDay[],
getModifiers: (day: CalendarDay) => Modifiers,
isSelected: (date: Date) => boolean,
lastFocused: CalendarDay | undefined
): CalendarDay | undefined {
let focusTarget: CalendarDay | undefined;
let foundFocusTargetPriority: FocusTargetPriority | -1 = -1;
for (const day of days) {
const modifiers = getModifiers(day);
if (isFocusableDay(modifiers)) {
if (
modifiers[DayFlag.focused] &&
foundFocusTargetPriority < FocusTargetPriority.FocusedModifier
) {
focusTarget = day;
foundFocusTargetPriority = FocusTargetPriority.FocusedModifier;
} else if (
lastFocused?.isEqualTo(day) &&
foundFocusTargetPriority < FocusTargetPriority.LastFocused
) {
focusTarget = day;
foundFocusTargetPriority = FocusTargetPriority.LastFocused;
} else if (
isSelected(day.date) &&
foundFocusTargetPriority < FocusTargetPriority.Selected
) {
focusTarget = day;
foundFocusTargetPriority = FocusTargetPriority.Selected;
} else if (
modifiers[DayFlag.today] &&
foundFocusTargetPriority < FocusTargetPriority.Today
) {
focusTarget = day;
foundFocusTargetPriority = FocusTargetPriority.Today;
}
}
}
if (!focusTarget) {
// Return the first day that is focusable
focusTarget = days.find((day) => isFocusableDay(getModifiers(day)));
}
return focusTarget;
}