list_times_in_google_calendar - google app script

Code.gs

// To list available Google Calendar times as text
// Create this function at https://script.google.com/
// Run the app and authorize it access Google Calendar
//


function listAvailableTimes() {
  // Define the calendar and the time period to check for availability
  var calendarId = 'primary'; // Use 'primary' for the primary calendar or the calendar ID for a specific calendar
  var startTime = new Date(); // Start from the current time
  var endTime = new Date();
  endTime.setDate(startTime.getDate() + 7); // Check for the next 7 days

  // Fetch events within the specified time range
  var events = CalendarApp.getCalendarById(calendarId).getEvents(startTime, endTime);

  // Define working hours (e.g., 9 AM to 5 PM)
  var workStartHour = 9;
  var workEndHour = 17;

  var availableTimes = [];
  var currentTime = new Date(startTime);
  currentTime.setHours(workStartHour, 0, 0, 0); // Start from the beginning of the working day

  while (currentTime < endTime) {
    var isFree = true;
    for (var i = 0; i < events.length; i++) {
      var event = events[i];
      if (event.isAllDayEvent() || (event.getStartTime() <= currentTime && event.getEndTime() > currentTime)) {
        isFree = false;
        currentTime = event.getEndTime();
        break;
      }
    }

    if (isFree) {
      var endTimeSlot = new Date(currentTime);
      endTimeSlot.setMinutes(currentTime.getMinutes() + 30); // Check for 30-minute slots
      if (endTimeSlot.getHours() > workEndHour || endTimeSlot > endTime) {
        currentTime.setHours(workStartHour, 0, 0, 0); // Move to the next day
        currentTime.setDate(currentTime.getDate() + 1);
        continue;
      }
      availableTimes.push(formatTimeSlot(currentTime, endTimeSlot));
      currentTime.setMinutes(currentTime.getMinutes() + 30);
    }
  }

  // Log the available times (or you can do something else with them, like send an email)
  Logger.log(availableTimes.join('\n'));
}

function formatTimeSlot(startTime, endTime) {
  var days = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];
  var startDay = days[startTime.getDay()];
  var startHours = startTime.getHours();
  var startMinutes = startTime.getMinutes();
  var endHours = endTime.getHours();
  var endMinutes = endTime.getMinutes();

  return Utilities.formatString('%02d:%02d %s - %02d:%02d %s %s',
    startHours, startMinutes, (startHours >= 12 ? 'PM' : 'AM'),
    endHours, endMinutes, (endHours >= 12 ? 'PM' : 'AM'),
    startDay);
}