getIsoTimeString.cfm

<cfscript>
/**
 * Converts your date into a time string the aheres to the ISO 8601 standard (for use with some API calls).
 * v1.0 by Ben Nadel
 * https://cflib.org/udf/getIsoTimeString
 * @param datetime      A date/time object (Required)
 * @param convertToUTC      Whether to convert to UTC before formatting (default true) (Optional)
 * @return A date string as per ISO format 
 * @author Ben Nadel (ben@bennadel.com) 
 * @version 1.0, August 1, 2013 
 * @version 2.0 May 10, 2017 by James Moberg/SunStar Media; Return empty string for non-date values. Return UTC offset (instead of Z).
 * Tested CF2016+ and Lucee
 * Gist: https://gist.github.com/JamoCA/5985859240f14ce8b73c1897fcc16970
 */
public string function getISOTimeString(string datetime, boolean convertToUTC=true) output=false hint="Converts your date into a time string the adheres to the ISO 8601 standard" {
	if (!isvalid("date", arguments.datetime)){
		return "";
	}
	local.mask = "yyyy-mm-dd'T'HH:nn:ssZ";
	if (arguments.convertToUTC) {
		/* ACF doesn't like empty timezone values. Only GMT works, not UTC. */
		return replace(datetimeformat(arguments.datetime, local.mask, "gmt"), "+0000", "Z");
	}
	return replace(datetimeformat(arguments.datetime, local.mask), "+0000", "Z");
}
</cfscript>