src/js/util/helper.js
function tz_offset_to_minutes(offset) {
	if (offset == "Z") {
		return 0
	}

	var offset = offset.split(":")

	if(offset.length == 1) {
		offset = offset[0]
		split_loc = offset.length - 2
		offset = [offset.substring(0, split_loc), offset.substring(split_loc)]
	}
	sign = offset[0].indexOf("-") > -1 ? -1 : 1

	offset = offset.map(parseFloat)

	return (offset[0]*60) + (sign * offset[1])
}
function tz_offset_to_minutes(offset) {
	if (offset == "Z") {
		return 0
	}

	var offset = offset.split(":")

	if(offset.length == 1) {
		offset = offset[0]
		split_loc = offset.length - 2
		offset = [offset.substring(0, split_loc), offset.substring(split_loc)]
	}
	sign = offset[0].indexOf("-") > -1 ? -1 : 1

	offset = offset.map(parseFloat)

	return (offset[0]*60) + (sign * offset[1])
}
Given a timezone offset in an hour:minute format and return the equivalent
number of minutes as a number
only exist in the source object.
@param {object} offset - A string in a hh:mm format or "Z" for no offset
@returns {number} - Number of minutes
@static
@memberof helper