From 0fe27bc6193537f27e728766fde1422a7a63c706 Mon Sep 17 00:00:00 2001
From: Rogier Schouten <github@workingcode.ninja>
Date: Thu, 6 May 2021 10:23:43 +0200
Subject: [PATCH] Fix for #56

---
 src/lib/basics.ts       | 2 +-
 src/test/test-basics.ts | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/lib/basics.ts b/src/lib/basics.ts
index 1d4a9f0..4f453fe 100644
--- a/src/lib/basics.ts
+++ b/src/lib/basics.ts
@@ -373,7 +373,7 @@ export function weekOfMonth(year: number, month: number, day: number): number {
 			// Last week of previous month
 			if (month > 1) {
 				// Default case
-				return weekOfMonth(year, month - 1, 31);
+				return weekOfMonth(year, month - 1, daysInMonth(year, month - 1));
 			} else {
 				// January
 				return weekOfMonth(year - 1, 12, 31);
diff --git a/src/test/test-basics.ts b/src/test/test-basics.ts
index 8065c72..2cf8e6f 100644
--- a/src/test/test-basics.ts
+++ b/src/test/test-basics.ts
@@ -449,6 +449,10 @@ describe("weekOfMonth()", (): void => {
 		expect(basics.weekOfMonth(2016, 1, 3)).to.equal(5);
 		expect(basics.weekOfMonth(2016, 1, 4)).to.equal(1);
 	});
+
+	it("should not have issue #56", (): void => {
+		expect(basics.weekOfMonth(2021, 5, 1)).to.equal(5);
+	});
 });
 
 describe("secondsInDay()", (): void => {