make a multiple fields comparator for sort functions

propertyComparator.js

/**
 * return a comparator to use in Array.sort method context.
 * take a list of properties (array or string delimited by pipe or comma) which you want to use for sort
 * @param {(string|string[])) fields list of properties names (array or string delimited by pipe or comma) which you want to use for sort
 *                                       each field name may be prefixed by an < or > to sort on ascending or descending order
 *                                       you can use n< or n> as prefix for a natural order sorting
 * @returns {function(object, object)}
 */
function propertyComparator(compareConfig) {
	if (typeof compareConfig === 'string') {
		compareConfig = compareConfig.split(/[|,]/);
	}

	let propertyName = compareConfig.shift();
	let isDescending = false;
	let isNatural = false;
	const next = compareConfig.length ? propertyComparator(compareConfig) : () => 0;
	const [comparatorConfig, naturalFlag, orderSymbol] = propertyName.match(/^(n?)(<|>)/) || ['', '', ''];

	if (comparatorConfig) {
		naturalFlag === 'n' && (isNatural = true);
		orderSymbol === '>' && (isDescending = true);
		propertyName = propertyName.slice(comparatorConfig.length);
	}

	const comparator = propertyComparator[isNatural ? 'createNaturalComparator' : 'createBasicComparator'](propertyName);

	if (isDescending) {
		return (a, b) => comparator(b, a) || next(a, b);
	}
	return (a, b) => comparator(a, b) || next(a, b);
}

/**
 * create a basic comparator between two objects based on given property name
 * @param {string} propertyName name of the property used for comparison
 * @returns {function(object, object)}
 */
propertyComparator.prototype.createBasicComparator = (propertyName) => {
	return (a, b) => {
		if (a[propertyName] > b[propertyName]) {
			return 1;
		}
		return a[propertyName] < b[propertyName] ? -1 : 0;
	};
};

/**
 * create a natural comparator between two objects based on given property name
 * @param {string} propertyName name of the property used for comparison
 * @returns {function(object, object)}
 */
propertyComparator.prototype.createNaturalComparator = (fieldName) => {
	if (String.prototype.localeCompare) {
		return (a, b) => a[fieldName].localeCompare(b[fieldName], undefined, { numeric: true });
	} else {
		return propertyComparator.createBasicComparator(fieldName);
	}
};