CalendarEvent color - colors

Question

When I create a Calendar Event manually, there is the possibility to give special colors to the event.
How can I access / change this color with a script? Searched all docs but found color only on the calendar-level, not on the event-level.

Answer 1

"colorId" is a string property of an event resource.
https://developers.google.com/google-apps/calendar/v3/reference/events#resource

Answer 2

The new Advanced Calendar Service allows you to do this now. Check out sample code under "Creating events" header:
https://developers.google.com/apps-script/advanced/calendar
I will paste it below in case the change the help page:
function createEvent() {
var calendarId = 'primary';
var start = getRelativeDate(1, 12);
var end = getRelativeDate(1, 13);
var event = {
summary: 'Lunch Meeting',
location: 'The Deli',
description: 'To discuss our plans for the presentation next week.',
start: {
dateTime: start.toISOString()
},
end: {
dateTime: end.toISOString()
},
attendees: [
{email: 'alice#example.com'},
{email: 'bob#example.com'}
],
// Red background. Use Calendar.Colors.get() for the full list.
colorId: 11
};
event = Calendar.Events.insert(event, calendarId);
Logger.log('Event ID: ' + event.getId());
}
/**
* Helper function to get a new Date object relative to the current date.
* #param {number} daysOffset The number of days in the future for the new date.
* #param {number} hour The hour of the day for the new date, in the time zone
* of the script.
* #return {Date} The new date.
*/
function getRelativeDate(daysOffset, hour) {
var date = new Date();
date.setDate(date.getDate() + daysOffset);
date.setHours(hour);
date.setMinutes(0);
date.setSeconds(0);
date.setMilliseconds(0);
return date;
}

Answer 3

The other answer refers to the calendar API that you can eventually access but it's not part of the standard calendar methods available in GAS.
You can simplify your life by making use of a Library that has been developed by Romain Vialard (gas top contributor) and that is available on his website along with an application I wrote that uses it extensively
edit : there is also an enhancement request on this on the issue tracker that I raised a while ago, feel free to star it.