function normalizeOptions(options = {}) {
	const hasGroups = options.groups && options.groups.length > 0;
	const groups = hasGroups ? options.groups : DEFAULT_GROUPS;
	const allowSamePrecedence = options.allowSamePrecedence !== false;

	return {
		groups,
		allowSamePrecedence,
	};
}
Normalizes options.
@param {Object|undefined} options A options object to normalize.
@returns {Object} Normalized option object.