Document firstDayOfWeek

zooniverse · Oct 29, 2024 · a545072 · a545072
1 parent 68d92ea
commit a545072
Showing 1 changed file with 8 additions and 2 deletions.
diff --git a/packages/app-project/stores/User/UserPersonalization/YourStats/YourStats.js b/packages/app-project/stores/User/UserPersonalization/YourStats/YourStats.js
@@ -28,8 +28,14 @@ export const statsClient = {
   }
 }
 
-// https://stackoverflow.com/a/51918448/10951669
-function firstDayOfWeek (dateUTCObject, firstDayOfWeekIndex) {
+/**
+ * Find the first day matching a given weekday number, prior to a given UTC date.
+ * https://stackoverflow.com/a/51918448/10951669
+ * @param {Date} dateUTCObject search prior to this UTC datetime.
+ * @param {number} firstDayOfWeekIndex day of the week to find (Sunday is 0.)
+ * @returns a UTC date object for the first day of the week
+ */
+function firstDayOfWeek(dateUTCObject, firstDayOfWeekIndex) {
   const dayOfWeek = dateUTCObject.getUTCDay()
   const firstDayOfWeek = new Date(dateUTCObject)
   const diff = dayOfWeek >= firstDayOfWeekIndex