Change return type of getDateInPast to Date

The previous return type was a date string.

This approach allows more flexibility when working
with the response.

app/assets/javascripts/lib/utils/datetime_utility.js

@@ -553,14 +553,10 @@ export const calculateRemainingMilliseconds = endDate => {
  *
  * @param {Date} date the date that we will substract days from
  * @param {number} daysInPast number of days that are subtracted from a given date
- * @returns {String} Date string in ISO format
+ * @returns {Date} Date in past as Date object
  */
-export const getDateInPast = (date, daysInPast) => {
-  const dateClone = newDate(date);
-  return new Date(
-    dateClone.setTime(dateClone.getTime() - daysInPast * 24 * 60 * 60 * 1000),
-  ).toISOString();
-};
+export const getDateInPast = (date, daysInPast) =>
+  new Date(newDate(date).setDate(date.getDate() - daysInPast));
 
 export const beginOfDayTime = 'T00:00:00Z';
 export const endOfDayTime = 'T23:59:59Z';

changelogs/unreleased/34755-refactor-getdateinpast-to-return-date-object.yml

+---
+title: Change return type of getDateInPast to Date
+merge_request: 19081
+author:
+type: changed

ee/app/assets/javascripts/analytics/cycle_analytics/components/base.vue

@@ -119,7 +119,7 @@ export default {
     },
     initDateRange() {
       const endDate = new Date(Date.now());
-      const startDate = new Date(getDateInPast(endDate, DEFAULT_DAYS_IN_PAST));
+      const startDate = getDateInPast(endDate, DEFAULT_DAYS_IN_PAST);
       this.setDateRange({ skipFetch: true, startDate, endDate });
     },
   },

ee/app/assets/javascripts/analytics/productivity_analytics/index.js

@@ -22,7 +22,7 @@ export default () => {
   const { endpoint, emptyStateSvgPath, noAccessSvgPath } = appContainer.dataset;
 
   const now = new Date(Date.now());
-  const defaultStartDate = new Date(getDateInPast(now, defaultDaysInPast));
+  const defaultStartDate = getDateInPast(now, defaultDaysInPast);
   const defaultEndDate = now;
 
   let filterManager;

ee/app/assets/javascripts/analytics/productivity_analytics/store/modules/charts/actions.js

@@ -33,7 +33,7 @@ export const fetchChartData = ({ dispatch, getters, state, rootState }, chartKey
         if (chartKey === chartKeys.scatterplot) {
           const transformedData = transformScatterData(
             data,
-            new Date(getDateInPast(rootState.filters.startDate, scatterPlotAddonQueryDays)),
+            getDateInPast(rootState.filters.startDate, scatterPlotAddonQueryDays),
             new Date(rootState.filters.endDate),
           );
 

ee/app/assets/javascripts/analytics/productivity_analytics/store/modules/filters/getters.js

@@ -27,10 +27,7 @@ export const getCommonFilterParams = state => chartKey => {
   // for the scatterplot we need to remove 30 days from the state's merged_at_after date
   const mergedAtAfterDate =
     chartKey && chartKey === chartKeys.scatterplot
-      ? dateFormat(
-          new Date(getDateInPast(new Date(startDate), scatterPlotAddonQueryDays)),
-          dateFormats.isoDate,
-        )
+      ? dateFormat(getDateInPast(startDate, scatterPlotAddonQueryDays), dateFormats.isoDate)
       : dateFormat(startDate, dateFormats.isoDate);
 
   return {

ee/app/assets/javascripts/analytics/productivity_analytics/utils.js

@@ -163,7 +163,7 @@ export const getMedianLineData = (data, startDate, endDate, daysOffset) => {
       medianData = transformedData.slice(startIndex, i);
       flattenedData = _.flatten(medianData);
       if (flattenedData.length) {
-        d = getDateInPast(endDate, len - i);
+        d = getDateInPast(endDate, len - i).toISOString();
         result.push([dateFormat(d, dateFormats.isoDate), median(flattenedData)]);
       }
     }

ee/spec/frontend/analytics/cycle_analytics/mock_data.js

@@ -51,7 +51,7 @@ const stageFixtures = defaultStages.reduce((acc, stage) => {
 }, {});
 
 export const endDate = new Date(Date.now());
-export const startDate = new Date(getDateInPast(endDate, DEFAULT_DAYS_IN_PAST));
+export const startDate = getDateInPast(endDate, DEFAULT_DAYS_IN_PAST);
 
 export const issueEvents = stageFixtures.issue;
 export const planEvents = stageFixtures.plan;

ee/spec/frontend/analytics/productivity_analytics/store/modules/charts/actions_spec.js

@@ -31,8 +31,8 @@ describe('Productivity analytics chart actions', () => {
       rootState: {
         endpoint: `${TEST_HOST}/analytics/productivity_analytics.json`,
         filters: {
-          startDate: '2019-09-01',
-          endDate: '2091-09-05',
+          startDate: new Date('2019-09-01'),
+          endDate: new Date('2091-09-05'),
         },
       },
       getters: {

spec/frontend/lib/utils/datetime_utility_spec.js

@@ -428,17 +428,19 @@ describe('newDate', () => {
 });
 
 describe('getDateInPast', () => {
-  const date = new Date(1563235200000); // 2019-07-16T00:00:00.000Z;
+  const date = new Date('2019-07-16T00:00:00.000Z');
   const daysInPast = 90;
 
   it('returns the correct date in the past', () => {
     const dateInPast = datetimeUtility.getDateInPast(date, daysInPast);
-    expect(dateInPast).toBe('2019-04-17T00:00:00.000Z');
+    const expectedDateInPast = new Date('2019-04-17T00:00:00.000Z');
+
+    expect(dateInPast).toStrictEqual(expectedDateInPast);
   });
 
   it('does not modifiy the original date', () => {
     datetimeUtility.getDateInPast(date, daysInPast);
-    expect(date).toStrictEqual(new Date(1563235200000));
+    expect(date).toStrictEqual(new Date('2019-07-16T00:00:00.000Z'));
   });
 });