fix(scheduler-core): process DST correctly

package.json

@@ -50,13 +50,14 @@
     "build:site:watch": "npx nodemon --exec \"yarn build:site:docs\" --watch \"packages/dx-react-grid-demos/dist/\" --watch \"packages/dx-react-chart-demos/dist/\" --watch \"packages/dx-react-scheduler-demos/dist/\" --watch \"packages/*/docs/\" --watch \"packages/*/demos/\" --watch \"gulpfile.js\" --ext md,js",
     "lint": "lerna run lint --ignore @devexpress/dx-vue-*",
     "lint:ci": "lerna run lint:ci",
-    "test": "lerna run test --ignore @devexpress/dx-vue-* && yarn test:bs4",
-    "test:ci": "yarn update-api:ci && lerna run test --ignore @devexpress/dx-vue-* -- -- --maxWorkers=1 --max-old-space-size=4096 && yarn test:bs4",
+    "test": "lerna run test --ignore @devexpress/dx-vue-* && yarn test:bs4 && yarn test:scheduler:pacific",
+    "test:ci": "yarn update-api:ci && lerna run test --ignore @devexpress/dx-vue-* -- -- --maxWorkers=1 --max-old-space-size=4096 && yarn test:bs4 && yarn test:scheduler:pacific",
     "testcafe:ci": "start-server-and-test start-demo-servers \"3002|3004|3005\" testcafe:ci:start",
     "testcafe:ci:start": "testcafe -q",
     "testcafe:local": "start-server-and-test start-demo-servers \"3002|3004|3005\" testcafe:local:start",
     "testcafe:local:start": "testcafe chrome ./**/*.testcafe.js --skip-js-errors",
     "test:bs4": "jest packages/dx-react-bootstrap4 --ci --silent --runInBand --bail",
+    "test:scheduler:pacific": "TZ=US/Pacific jest packages/dx-scheduler-core --ci --silent --runInBand --bail",
     "test:watch": "jest --watch",
     "publish:prepare": "yarn && node ./scripts/prepare-commit.js",
     "publish:npm": "yarn && node ./scripts/publish-npm.js",

packages/dx-grid-core/src/plugins/custom-tree-data/computeds.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import { GRID_TREE_NODE_TYPE } from './constants';
 import {
   customTreeRowsWithMeta,

packages/dx-grid-core/src/plugins/filtering-state/reducers.test.ts

@@ -1,5 +1,6 @@
 import { changeColumnFilter } from './reducers';
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 
 describe('FilteringState reducers', () => {
   describe('#changeColumnFilter', () => {

packages/dx-grid-core/src/plugins/grouping-state/reducers.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import {
   changeColumnGrouping,
   draftColumnGrouping,

packages/dx-grid-core/src/plugins/integrated-grouping/computeds.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import {
   groupRowChecker,
   groupRowLevelKeyGetter,

packages/dx-grid-core/src/plugins/integrated-sorting/computeds.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import { sortedRows } from './computeds';
 import { Sorting } from '../../types';
 

packages/dx-grid-core/src/plugins/sorting-state/reducers.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import { ReadonlyObject } from '@devexpress/dx-core';
 import { changeColumnSorting } from './reducers';
 import { ColumnSortingState, ChangeSortingPayload } from '../../types';

packages/dx-grid-core/src/plugins/table-band-header/helpers.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import {
   TABLE_BAND_TYPE, BAND_GROUP_CELL, BAND_HEADER_CELL, BAND_EMPTY_CELL, BAND_DUPLICATE_RENDER,
   BAND_FILL_LEVEL_CELL,

packages/dx-grid-core/src/plugins/table-column-reordering/computeds.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import { TABLE_DATA_TYPE } from '../table/constants';
 import { TABLE_REORDERING_TYPE } from './constants';
 import {

packages/dx-grid-core/src/plugins/table-column-reordering/reducers.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import { changeColumnOrder } from './reducers';
 
 describe('TableColumnReordering reducers', () => {

packages/dx-grid-core/src/plugins/table-column-resizing/helpers.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import {
   getColumnSizes,
   isValidValue,

packages/dx-grid-core/src/plugins/table-column-resizing/reducers.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import {
   changeTableColumnWidth,
   draftTableColumnWidth,

packages/dx-grid-core/src/plugins/table-edit-row/computeds.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import { TABLE_ADDED_TYPE, TABLE_EDIT_TYPE } from './constants';
 import { TABLE_DATA_TYPE } from '../table/constants';
 import { tableRowsWithEditing } from './computeds';

packages/dx-grid-core/src/plugins/table-fixed-columns/helpers.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import { TABLE_DATA_TYPE } from '../table/constants';
 import { FIXED_COLUMN_LEFT_SIDE, FIXED_COLUMN_RIGHT_SIDE, TABLE_FIXED_TYPE } from './constants';
 import { getFixedColumnKeys, isFixedTableRow, calculateFixedColumnProps } from './helpers';

packages/dx-grid-core/src/utils/merge-sort.test.ts

@@ -1,4 +1,5 @@
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import mergeSort from './merge-sort';
 
 describe('margeSort', () => {

packages/dx-react-grid/src/components/table-layout.test.tsx

@@ -3,7 +3,8 @@
 import * as React from 'react';
 import { findDOMNode } from 'react-dom';
 import { shallow, mount } from 'enzyme';
-import * as Immutable from 'seamless-immutable';
+// tslint:disable-next-line: import-name
+import Immutable from 'seamless-immutable';
 import {
   getAnimations,
   filterActiveAnimations,

packages/dx-scheduler-core/package.json

@@ -30,6 +30,7 @@
   ],
   "scripts": {
     "test": "jest",
+    "test:pacific": "TZ=US/Pacific jest",
     "test:watch": "jest --watch",
     "test:coverage": "jest --coverage",
     "build": "rollup -c rollup.config.js",

packages/dx-scheduler-core/src/plugins/common/computeds.test.ts

@@ -155,6 +155,54 @@ describe('#timeScale', () => {
     expect(units[2].end.getHours()).toBe(23);
     expect(units[2].end.getMinutes()).toBe(59);
   });
+
+  it('should work correctly if current day contains DST change', () => {
+    const dateWithDSTChange = new Date('2020-11-01T00:00:00');
+    const units = timeScale(dateWithDSTChange, 0, 0, 4, 30);
+
+    expect(units.length).toBe(8);
+
+    expect(units[0].start.getHours()).toBe(0);
+    expect(units[0].start.getMinutes()).toBe(0);
+    expect(units[0].end.getHours()).toBe(0);
+    expect(units[0].end.getMinutes()).toBe(30);
+
+    expect(units[1].start.getHours()).toBe(0);
+    expect(units[1].start.getMinutes()).toBe(30);
+    expect(units[1].end.getHours()).toBe(1);
+    expect(units[1].end.getMinutes()).toBe(0);
+
+    expect(units[2].start.getHours()).toBe(1);
+    expect(units[2].start.getMinutes()).toBe(0);
+    expect(units[2].end.getHours()).toBe(1);
+    expect(units[2].end.getMinutes()).toBe(30);
+
+    expect(units[3].start.getHours()).toBe(1);
+    expect(units[3].start.getMinutes()).toBe(30);
+    expect(units[3].end.getHours()).toBe(2);
+    expect(units[3].end.getMinutes()).toBe(0);
+
+    expect(units[4].start.getHours()).toBe(2);
+    expect(units[4].start.getMinutes()).toBe(0);
+    expect(units[4].end.getHours()).toBe(2);
+    expect(units[4].end.getMinutes()).toBe(30);
+
+    expect(units[5].start.getHours()).toBe(2);
+    expect(units[5].start.getMinutes()).toBe(30);
+    expect(units[5].end.getHours()).toBe(3);
+    expect(units[5].end.getMinutes()).toBe(0);
+
+    expect(units[6].start.getHours()).toBe(3);
+    expect(units[6].start.getMinutes()).toBe(0);
+    expect(units[6].end.getHours()).toBe(3);
+    expect(units[6].end.getMinutes()).toBe(30);
+
+    expect(units[7].start.getHours()).toBe(3);
+    expect(units[7].start.getMinutes()).toBe(30);
+    expect(units[7].end.getHours()).toBe(4);
+    expect(units[7].end.getMinutes()).toBe(0);
+
+  });
 });
 
 describe('#availableViews', () => {

packages/dx-scheduler-core/src/plugins/common/computeds.ts

@@ -31,6 +31,17 @@ export const dayScale: DayScaleFn = (
   return result;
 };
 
+const containsDSTChange = (date: SchedulerDateTime) => {
+  const momentDate = moment(date);
+  momentDate.startOf('day');
+  const isStartDST = momentDate.isDST();
+
+  momentDate.endOf('day');
+  const isEndDst = momentDate.isDST();
+
+  return (isStartDST && !isEndDst) || (!isStartDST && isEndDst);
+};
+
 export const timeScale: TimeScaleFn = (
   currentDate,
   firstDayOfWeek,
@@ -43,10 +54,17 @@ export const timeScale: TimeScaleFn = (
   const startDateOfView = firstDayOfWeek !== undefined
     ? calculateFirstDateOfWeek(currentDate, firstDayOfWeek, excludedDays)
     : currentDate;
-  const left = moment(startDateOfView as Date)
+
+  const isDSTChange = containsDSTChange(startDateOfView as Date);
+  const validDate = moment(startDateOfView as Date);
+  if (isDSTChange) {
+    validDate.subtract(1, 'day');
+  }
+
+  const left = moment(validDate)
     .startOf('day')
     .add(startDayHour, 'hour');
-  const right = moment(startDateOfView as Date)
+  const right = moment(validDate)
     .startOf('day')
     .add(endDayHour, 'hour');
 
@@ -86,7 +104,6 @@ export const viewCellsData: ViewCellsDataFn = (
     currentDate, firstDayOfWeek!, startDayHour, endDayHour, cellDuration, excludedDays,
   );
   const currentTime = moment(currTime as SchedulerDateTime);
-
   return times.reduce((cellsAcc, time) => {
     const start = moment(time.start);
     const end = moment(time.end);

packages/dx-scheduler-core/src/utils.test.ts

@@ -11,6 +11,8 @@ import {
 } from './utils';
 import { addDateToKey } from '.';
 
+const PACIFIC_TIMEZONE_OFFSET = 480;
+
 describe('Utils', () => {
   describe('#viewPredicate', () => {
     it('should filter outside appointments', () => {
@@ -395,28 +397,31 @@ describe('Utils', () => {
       expect(result[1].end.toString())
         .toBe(moment(new Date('2019-04-26T23:00:00+0300')).toString());
     });
-    it('should work with recurrence appointment with UNTIL set', () => {
-      const monthlyLeftBound = new Date('2019-04-1 00:00');
-      const monthlyRightBound = new Date('2019-05-30 00:00');
-      const appointment = {
-        start: moment(new Date('2019-04-9 00:00')),
-        end: moment(new Date('2019-04-9 23:59')),
-        rRule: 'FREQ=DAILY;UNTIL=20190410T000000Z',
-      };
-      const result = filterByViewBoundaries(appointment, monthlyLeftBound, monthlyRightBound);
 
-      expect(result).toHaveLength(2);
-
-      expect(result[0].start.toString())
-        .toBe(moment(new Date('2019-04-09 0:00')).toString());
-      expect(result[0].end.toString())
-        .toBe(moment(new Date('2019-04-09 23:59')).toString());
-
-      expect(result[1].start.toString())
-        .toBe(moment(new Date('2019-04-10 0:00')).toString());
-      expect(result[1].end.toString())
-        .toBe(moment(new Date('2019-04-10 23:59')).toString());
-    });
+    if ((new Date(2020, 2, 7)).getTimezoneOffset() !== PACIFIC_TIMEZONE_OFFSET) {
+      it('should work with recurrence appointment with UNTIL set', () => {
+        const monthlyLeftBound = new Date('2019-04-1 00:00');
+        const monthlyRightBound = new Date('2019-05-30 00:00');
+        const appointment = {
+          start: moment(new Date('2019-04-9 00:00')),
+          end: moment(new Date('2019-04-9 23:59')),
+          rRule: 'FREQ=DAILY;UNTIL=20190410T000000Z',
+        };
+        const result = filterByViewBoundaries(appointment, monthlyLeftBound, monthlyRightBound);
+
+        expect(result).toHaveLength(2);
+
+        expect(result[0].start.toString())
+          .toBe(moment(new Date('2019-04-09 0:00')).toString());
+        expect(result[0].end.toString())
+          .toBe(moment(new Date('2019-04-09 23:59')).toString());
+
+        expect(result[1].start.toString())
+          .toBe(moment(new Date('2019-04-10 0:00')).toString());
+        expect(result[1].end.toString())
+          .toBe(moment(new Date('2019-04-10 23:59')).toString());
+      });
+    }
   });
   describe('#getRRuleSetWithExDates', () => {
     it('should create RRuleSet', () => {

tsconfig.json

@@ -25,6 +25,7 @@
       "@devexpress/*":["packages/*/src"],
       "*": ["node_modules", "packages"]
     },
+    "esModuleInterop": true
   },
   "exclude": [
     "node_modules",