on timeline refresh, recompute "past week" date range

Within one app session, the constants TODAY_DATE and INITIAL_DATE_RANGE do not change. On app resume, we call refreshTimeline which sets dateRange to INITIAL_DATE_RANGE. But this is a problem if the app stays running for multiple days because INITIAL_DATE_RANGE is old.

Instead we need to recompute the date range, using an up-to-date "today" date. Thus, TODAY_DATE and INITIAL_DATE_RANGE are replaced with functions: getTodayDate and getPastWeekDateRange.

www/js/TimelineContext.ts

@@ -25,9 +25,12 @@ import useAppStateChange from './useAppStateChange';
 import { isoDateRangeToTsRange, isoDateWithOffset } from './datetimeUtil';
 import { base_modes } from 'e-mission-common';
 
-const TODAY_DATE = DateTime.now().toISODate();
+const getTodayDate = () => DateTime.now().toISODate();
 // initial date range is the past week: [TODAY - 6 days, TODAY]
-const INITIAL_DATE_RANGE: [string, string] = [isoDateWithOffset(TODAY_DATE, -6), TODAY_DATE];
+const getPastWeekDateRange = (): [string, string] => {
+  const todayDate = getTodayDate();
+  return [isoDateWithOffset(todayDate, -6), todayDate];
+};
 
 type ContextProps = {
   labelOptions: LabelOptions | null;
@@ -60,7 +63,7 @@ export const useTimelineContext = (): ContextProps => {
   // date range (inclusive) that has been loaded into the UI [YYYY-MM-DD, YYYY-MM-DD]
   const [queriedDateRange, setQueriedDateRange] = useState<[string, string] | null>(null);
   // date range (inclusive) chosen by datepicker [YYYY-MM-DD, YYYY-MM-DD]
-  const [dateRange, setDateRange] = useState<[string, string]>(INITIAL_DATE_RANGE);
+  const [dateRange, setDateRange] = useState<[string, string]>(getPastWeekDateRange);
   // map of timeline entries (trips, places, untracked time), ids to objects
   const [timelineMap, setTimelineMap] = useState<TimelineMap | null>(null);
   const [timelineIsLoading, setTimelineIsLoading] = useState<string | false>('replace');
@@ -184,7 +187,7 @@ export const useTimelineContext = (): ContextProps => {
     // clamp range to ensure it is within [pipelineStartDate, TODAY_DATE]
     const clampedDateRange: [string, string] = [
       new Date(range[0]) < new Date(pipelineStartDate) ? pipelineStartDate : range[0],
-      new Date(range[1]) > new Date(TODAY_DATE) ? TODAY_DATE : range[1],
+      new Date(range[1]) > new Date(getTodayDate()) ? getTodayDate() : range[1],
     ];
     if (clampedDateRange[0] != dateRange?.[0] || clampedDateRange[1] != dateRange?.[1]) {
       logDebug('Timeline: loadDateRange setting new date range = ' + clampedDateRange);
@@ -257,7 +260,7 @@ export const useTimelineContext = (): ContextProps => {
     try {
       logDebug('timelineContext: refreshTimeline');
       setTimelineIsLoading('replace');
-      setDateRange(INITIAL_DATE_RANGE);
+      setDateRange(getPastWeekDateRange());
       setQueriedDateRange(null);
       setTimelineMap(null);
       setRefreshTime(new Date());