Function compareIterables

lib/util/comparators.js:97–123

(elementComparator)

 * @returns {Comparator<Iterable<T>>} comparator for iterables of elements
 */
const compareIterables = (elementComparator) => {
	const cacheEntry = compareIteratorsCache.get(elementComparator);
	if (cacheEntry !== undefined) return cacheEntry;
	/**
	 * Returns compare result.
	 * @param {Iterable<T>} a first value
	 * @param {Iterable<T>} b second value
	 * @returns {-1 | 0 | 1} compare result
	 */
	const result = (a, b) => {
		const aI = a[Symbol.iterator]();
		const bI = b[Symbol.iterator]();
		while (true) {
			const aItem = aI.next();
			const bItem = bI.next();
			if (aItem.done) {
				return bItem.done ? 0 : -1;
			} else if (bItem.done) {
				return 1;
			}
			const res = elementComparator(aItem.value, bItem.value);
			if (res !== 0) return res;
		}
	};
	compareIteratorsCache.set(elementComparator, result);
	return result;
};

/**
 * Compare two locations