From 290a4c18bfb8a8113741442743e00c471d224295 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ivar=20Conradi=20=C3=98sthus?= <ivarconr@gmail.com>
Date: Fri, 8 Oct 2021 09:53:33 +0200
Subject: [PATCH] fix: use modulo instead for Math.floor for rounding down to
 full hour

---
 src/lib/db/client-metrics-store-v2.ts               |  5 +----
 .../e2e/stores/client-metrics-store-v2.e2e.test.ts  | 13 +++++++++++++
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/lib/db/client-metrics-store-v2.ts b/src/lib/db/client-metrics-store-v2.ts
index 8e77e88db8..e3ac091369 100644
--- a/src/lib/db/client-metrics-store-v2.ts
+++ b/src/lib/db/client-metrics-store-v2.ts
@@ -1,5 +1,4 @@
 /* eslint-disable @typescript-eslint/no-unused-vars */
-import util from 'util';
 import { Knex } from 'knex';
 import { Logger, LogProvider } from '../logger';
 import {
@@ -20,10 +19,8 @@ interface ClientMetricsEnvTable {
 
 const TABLE = 'client_metrics_env';
 
-// Unsure if this would be better be done by the service?
 export function roundDownToHour(date: Date): Date {
-    let p = 60 * 60 * 1000; // milliseconds in an hour
-    return new Date(Math.floor(date.getTime() / p) * p);
+    return new Date(date.getTime() - (date.getTime() % 3600000));
 }
 
 const fromRow = (row: ClientMetricsEnvTable) => ({
diff --git a/src/test/e2e/stores/client-metrics-store-v2.e2e.test.ts b/src/test/e2e/stores/client-metrics-store-v2.e2e.test.ts
index 271bd4bb18..5afb48edcb 100644
--- a/src/test/e2e/stores/client-metrics-store-v2.e2e.test.ts
+++ b/src/test/e2e/stores/client-metrics-store-v2.e2e.test.ts
@@ -5,6 +5,7 @@ import {
     IClientMetricsEnv,
     IClientMetricsStoreV2,
 } from '../../../lib/types/stores/client-metrics-store-v2';
+import { roundDownToHour } from '../../../lib/db/client-metrics-store-v2';
 
 let db;
 let stores: IUnleashStores;
@@ -382,3 +383,15 @@ test('Should not exists after delete', async () => {
     const existAfter = await clientMetricsStore.exists(metric);
     expect(existAfter).toBe(false);
 });
+
+test('should floor hours as expected', () => {
+    expect(
+        roundDownToHour(new Date('2019-11-12T08:44:32.499Z')).toISOString(),
+    ).toBe('2019-11-12T08:00:00.000Z');
+    expect(
+        roundDownToHour(new Date('2019-11-12T08:59:59.999Z')).toISOString(),
+    ).toBe('2019-11-12T08:00:00.000Z');
+    expect(
+        roundDownToHour(new Date('2019-11-12T09:01:00.999Z')).toISOString(),
+    ).toBe('2019-11-12T09:00:00.000Z');
+});