Fiz/daily date discrepancy (#15656)

* Refactor(tasks): Centralize daily task start date normalization

* fix datepicker server day shifts by zeroing time

---------

Co-authored-by: Hafiz <hafizbhamidi@gmail.com>

website/client/src/components/ui/datepicker.vue

@@ -68,8 +68,12 @@ export default {
   },
   methods: {
     upDate (after) {
-      this.value = after;
-      this.$emit('update:date', after);
+      // zero out the time so the server doesn't shift the day across a DST boundary on save
+      const normalized = after
+        ? new Date(after.getFullYear(), after.getMonth(), after.getDate())
+        : null;
+      this.value = normalized;
+      this.$emit('update:date', normalized);
     },
     setToday () {
       this.upDate(moment().toDate());

website/server/controllers/api-v3/tasks.js

@@ -27,6 +27,7 @@ import {
   moveTask,
   setNextDue,
   requiredGroupFields,
+  normalizeDailyStartDate,
 } from '../../libs/tasks/utils';
 import common from '../../../common';
 import { apiError } from '../../libs/apiError';
@@ -648,13 +649,10 @@ api.updateTask = {
       task.group.managerNotes = sanitizedObj.managerNotes;
     }
 
-    // For daily tasks, update start date based on timezone to maintain consistency
     if (task.type === 'daily'
         && task.startDate
     ) {
-      task.startDate = moment(task.startDate).utcOffset(
-        -user.preferences.timezoneOffset,
-      ).startOf('day').toDate();
+      task.startDate = normalizeDailyStartDate(task.startDate, user);
 
       // If the daily task was set to repeat monthly on a day of the month, and the start date was
       // updated, the task will then need to be updated to repeat on the same day of the month as

website/server/libs/tasks/index.js

@@ -1,4 +1,3 @@
-import moment from 'moment';
 import cloneDeep from 'lodash/cloneDeep';
 import compact from 'lodash/compact';
 import forEach from 'lodash/forEach';
@@ -9,6 +8,7 @@ import {
   setNextDue,
   validateTaskAlias,
   requiredGroupFields,
+  normalizeDailyStartDate,
 } from './utils';
 import { model as Challenge } from '../../models/challenge';
 import { model as Group } from '../../models/group';
@@ -80,13 +80,8 @@ async function createTasks (req, res, options = {}) {
       }
     }
 
-    // set startDate to midnight in the user's timezone
     if (taskType === 'daily') {
-      const awareStartDate = moment(newTask.startDate).utcOffset(-user.preferences.timezoneOffset);
-      if (awareStartDate.format('HMsS') !== '0000') {
-        awareStartDate.startOf('day');
-        newTask.startDate = awareStartDate.toDate();
-      }
+      newTask.startDate = normalizeDailyStartDate(newTask.startDate, user);
     }
 
     setNextDue(newTask, user);

website/server/libs/tasks/utils.js

@@ -59,6 +59,21 @@ export function moveTask (order, taskId, to) {
   }
 }
 
+export function normalizeDailyStartDate (date, user) {
+  if (!date) return date;
+  const utcView = moment.utc(date);
+  const looksLikeMidnightLocal = utcView.second() === 0
+    && utcView.millisecond() === 0
+    && [0, 15, 30, 45].includes(utcView.minute());
+  if (looksLikeMidnightLocal) {
+    return new Date(date);
+  }
+  return moment(date)
+    .utcOffset(-(user.preferences.timezoneOffset || 0))
+    .startOf('day')
+    .toDate();
+}
+
 export function setNextDue (task, user, dueDateOption) {
   if (task.type !== 'daily') return;