function parseRange(range) {
		var m = /^\s*(\d+)\s*(?:(,)\s*(?:(\d+)\s*)?)?$/.exec(range || '');
		if (m) {
			var start = Number(m[1]);
			var comma = m[2];
			var end = m[3];

			if (!comma) {
				return [start, start];
			}
			if (!end) {
				return [start, undefined];
			}
			return [start, Number(end)];
		}
		return undefined;
	}
Parses the given range.

This returns a range with inclusive ends.

@param {string | null | undefined} range
@returns {[number, number | undefined] | undefined}