Is interval.merge outputs the interval in ascending order ?

[nivekithan]

Let's say I call Interval.merge for an array of intervals. In that case, does the returned array of intervals sorted ? If yes, what order it is ascending or descending ?

Thanks

[dobon]

It is ascending order. Here's the relevant code, the sorting is on line 478.

luxon/src/interval.js

Lines 476 to 495 in 20139a3

	static merge(intervals) {
	const [found, final] = intervals
	.sort((a, b) => a.s - b.s)
	.reduce(
	([sofar, current], item) => {
	if (!current) {
	return [sofar, item];
	} else if (current.overlaps(item) || current.abutsStart(item)) {
	return [sofar, current.union(item)];
	} else {
	return [sofar.concat([current]), item];
	}
	},
	[[], null]
	);
	if (final) {
	found.push(final);
	}
	return found;
	}

And here is the relevant test. The test's input array with length 5 is converted to an ascending order output array with length 3 when merged.

luxon/test/interval/many.test.js

Lines 93 to 107 in 20139a3

	test("Interval.merge returns the minimal set of intervals", () => {
	const list = [
	todayFrom(5, 8),
	todayFrom(4, 7),
	todayFrom(10, 11),
	todayFrom(11, 12),
	todayFrom(13, 15),
	],
	results = Interval.merge(list);
	expect(results.length).toBe(3);
	expect(results[0] && results[0].equals(todayFrom(4, 8))).toBeTruthy();
	expect(results[1] && results[1].equals(todayFrom(10, 12))).toBeTruthy();
	expect(results[2] && results[2].equals(todayFrom(13, 15))).toBeTruthy();
	});

[nivekithan]

Thanks

[diesieben07]

I have added a note about this behavior to the documentation for Interval.merge:
4e37fa5