Timezone Behaviour

Schedule timezone vs. viewer timezone

• Schedule timezone (weeklySchedule.timezone) — The timezone in which your working hours are defined. For example, if you work 9–5 in London, use Europe/London.
• Viewer timezone (timezone in params) — The timezone in which you want results. Typically the end user's timezone. Slots and windows are returned in this timezone (e.g. "09:00", "17:00").

Example

Schedule: Mon–Fri 9–5 in Europe/London.
Viewer: America/New_York.

For Monday Dec 9, 2024:

• In London: 9–5 local.
• In New York: 4am–12pm EST (winter). The library returns slots in New York time so the viewer sees 04:00–12:00.

import {
  getAvailableTimeslots,
  DAY_OF_WEEK,
  type WeeklySchedule,
} from 'availability-js';

const weeklySchedule: WeeklySchedule = {
  schedule: [
    { dayOfWeek: DAY_OF_WEEK.Monday, start: '09:00', end: '17:00' },
  ],
  timezone: 'Europe/London',
};

const slots = getAvailableTimeslots({
  weeklySchedule,
  date: new Date('2024-12-09'),
  timezone: 'America/New_York',
  slotDurationMinutes: 60,
});

// Result (example):
// [
//   { start: '04:00', end: '05:00', isAvailable: true },
//   { start: '05:00', end: '06:00', isAvailable: true },
//   ...
//   { start: '11:00', end: '12:00', isAvailable: true },
// ]

Bookings in UTC

Bookings are always in UTC. The library converts between UTC and the viewer timezone when checking overlaps, so you don't need to convert manually.