make slider 30 seconds older to fix Date comparison and flicker

source/reddit-comments/constants.ts

@@ -78,6 +78,9 @@ export const databaseName = 'reddit-unread-comments-db';
 /** 2 * 10**12 */
 export const currentSessionCreatedAt = 2e12 as const;
 
+/** Offset in seconds to fix Date comparison 1hr > 1hr and prevent flicker. */
+export const dateCorrectionOffset = 30 as const;
+
 // tested
 /** Start deleting at. */
 export const dbSizeLimit: number = 1 * 1024 * 1024; // 1 MB limit

source/reddit-comments/datetime.ts

@@ -1,4 +1,5 @@
-import { sub, isToday, startOfDay, format } from 'date-fns';
+import { sub, format } from 'date-fns';
+import { dateCorrectionOffset } from './constants';
 
 import { SettingsData, TimeScaleType } from './database/schema';
 import { MyUnparsableDateException } from './exceptions';
@@ -101,5 +102,11 @@ export const radioAndSliderToDate = (
 
   const pastDate = sub(new Date(), { [unit]: timeSlider });
 
-  return pastDate;
+  // make the slider 30 seconds older than it is so the comment passes the filtering condition
+  // fixes flickering for 1hr > 1hr
+  // should be done exactly and only here
+  // sub = older, add = newer
+  const correctedPastDate = sub(pastDate, { seconds: dateCorrectionOffset });
+
+  return correctedPastDate;
 };

source/reddit-comments/dom.ts

@@ -155,7 +155,7 @@ const getFilteredNewerCommentsByDate = (
   const filteredComments = commentElements.filter((commentElement) => {
     const commentId = validateCommentElementIdOrThrow(commentElement);
     const commentDate = getDateFromCommentId(commentId); // here it throws
-    return commentDate.getTime() >= newerThan.getTime();
+    return commentDate.getTime() > newerThan.getTime();
   });
 
   return filteredComments;