Update range selection behavior

README.md

@@ -113,7 +113,8 @@ scroll                               | Object    | { enabled: false }| infinite
 showMonthArrow                       | Boolean   | true             | show/hide month arrow button
 navigatorRenderer                    | Func      |                  | renderer for focused date navigation area. fn(currentFocusedDate: Date, changeShownDate: func, props: object)
 ranges                               | *Object[] | []               | Defines ranges. array of range object
-moveRangeOnFirstSelection(DateRange) | Boolean   | false            | move range on startDate selection. Otherwise endDate will replace with startDate.
+moveRangeOnFirstSelection(DateRange) | Boolean   | false            | move range on startDate selection. Otherwise endDate will replace with startDate unless `retainEndDateOnFirstSelection` is set to true.
+retainEndDateOnFirstSelection(DateRange) | Boolean   | false            | Retain end date when the start date is changed, unless start date is later than end date. Ignored if `moveRangeOnFirstSelection` is set to true.
 onChange(Calendar)                   | Func      |                  | callback function for date changes. fn(date: Date)
 onChange(DateRange)                  | Func      |                  | callback function for range changes. fn(changes). changes contains changed ranges with new `startDate`/`endDate` properties.
 color(Calendar)                      | String    | `#3d91ff`        | defines color for selected date in Calendar

src/components/DateRange/README.md

@@ -3,9 +3,10 @@ This component extends all the props of **[Calendar](#calendar)** component. In
 | Prop Name  |  Type |
 |---|---|
 |  **moveRangeOnFirstSelection** |  boolean |
-|   **onRangeFocusChange** |  function |
-|   **rangeColors**  |  array |
-|   **ranges**  |  array |
+|  **retainEndDateOnFirstSelection** |  boolean |
+|  **onRangeFocusChange** |  function |
+|  **rangeColors**  |  array |
+|  **ranges**  |  array |
 
 
 #### Example: Editable Date Inputs

src/components/DateRange/index.js

@@ -18,22 +18,40 @@ class DateRange extends Component {
   }
   calcNewSelection = (value, isSingleValue = true) => {
     const focusedRange = this.props.focusedRange || this.state.focusedRange;
-    const { ranges, onChange, maxDate, moveRangeOnFirstSelection, disabledDates } = this.props;
+    const {
+      ranges,
+      onChange,
+      maxDate,
+      moveRangeOnFirstSelection,
+      retainEndDateOnFirstSelection,
+      disabledDates,
+    } = this.props;
     const focusedRangeIndex = focusedRange[0];
     const selectedRange = ranges[focusedRangeIndex];
     if (!selectedRange || !onChange) return {};
-
     let { startDate, endDate } = selectedRange;
-    if (!endDate) endDate = new Date(startDate);
+    const now = new Date();
     let nextFocusRange;
     if (!isSingleValue) {
       startDate = value.startDate;
       endDate = value.endDate;
     } else if (focusedRange[1] === 0) {
       // startDate selection
-      const dayOffset = differenceInCalendarDays(endDate, startDate);
+      const dayOffset = differenceInCalendarDays(endDate || now, startDate);
+      const calculateEndDate = () => {
+        if (moveRangeOnFirstSelection) {
+          return addDays(value, dayOffset);
+        }
+        if (retainEndDateOnFirstSelection) {
+          if (!endDate || isBefore(value, endDate)) {
+            return endDate;
+          }
+          return value;
+        }
+        return value || now;
+      };
       startDate = value;
-      endDate = moveRangeOnFirstSelection ? addDays(value, dayOffset) : value;
+      endDate = calculateEndDate();
       if (maxDate) endDate = min([endDate, maxDate]);
       nextFocusRange = [focusedRange[0], 1];
     } else {
@@ -131,6 +149,7 @@ DateRange.defaultProps = {
   classNames: {},
   ranges: [],
   moveRangeOnFirstSelection: false,
+  retainEndDateOnFirstSelection: false,
   rangeColors: ['#3d91ff', '#3ecf8e', '#fed14c'],
   disabledDates: [],
 };
@@ -142,6 +161,7 @@ DateRange.propTypes = {
   className: PropTypes.string,
   ranges: PropTypes.arrayOf(rangeShape),
   moveRangeOnFirstSelection: PropTypes.bool,
+  retainEndDateOnFirstSelection: PropTypes.bool,
 };
 
 export default DateRange;

src/components/DateRange/index.test.js

@@ -1,7 +1,84 @@
+import React from 'react';
+import { subDays, addDays, isSameDay } from 'date-fns';
 import DateRange from '../DateRange';
+import renderer from 'react-test-renderer';
+
+let testRenderer = null;
+let instance = null;
+const endDate = new Date();
+const startDate = subDays(endDate, 7);
+
+const commonProps = {
+  ranges: [{ startDate, endDate, key: 'selection' }],
+  onChange: () => {},
+  moveRangeOnFirstSelection: false,
+};
+
+const compareRanges = (newRange, assertionRange) => {
+  ['startDate', 'endDate'].forEach(key => {
+    if (!newRange[key] || !assertionRange[key]) {
+      return expect(newRange[key]).toEqual(assertionRange[key]);
+    }
+    return expect(isSameDay(newRange[key], assertionRange[key])).toEqual(true);
+  });
+};
+
+beforeEach(() => {
+  testRenderer = renderer.create(<DateRange {...commonProps} />);
+  instance = testRenderer.getInstance();
+});
 
 describe('DateRange', () => {
   test('Should resolve', () => {
     expect(DateRange).toEqual(expect.anything());
   });
+
+  test('calculate new selection by resetting end date', () => {
+    const methodResult = instance.calcNewSelection(subDays(endDate, 10), true);
+    compareRanges(methodResult.range, {
+      startDate: subDays(endDate, 10),
+      endDate: subDays(endDate, 10),
+    });
+  });
+
+  test('calculate new selection by resetting end date if start date is not before', () => {
+    const methodResult = instance.calcNewSelection(addDays(endDate, 2), true);
+    compareRanges(methodResult.range, {
+      startDate: addDays(endDate, 2),
+      endDate: addDays(endDate, 2),
+    });
+  });
+
+  test('calculate new selection based on moveRangeOnFirstSelection prop', () => {
+    testRenderer.update(<DateRange {...commonProps} moveRangeOnFirstSelection />);
+    const methodResult = instance.calcNewSelection(subDays(endDate, 10), true);
+    compareRanges(methodResult.range, {
+      startDate: subDays(endDate, 10),
+      endDate: subDays(endDate, 3),
+    });
+  });
+
+  test('calculate new selection by retaining end date, based on retainEndDateOnFirstSelection prop', () => {
+    testRenderer.update(<DateRange {...commonProps} retainEndDateOnFirstSelection />);
+    const methodResult = instance.calcNewSelection(subDays(endDate, 10), true);
+    compareRanges(methodResult.range, {
+      startDate: subDays(endDate, 10),
+      endDate,
+    });
+  });
+
+  test('calculate new selection by retaining the unset end date, based on retainEndDateOnFirstSelection prop', () => {
+    testRenderer.update(
+      <DateRange
+        {...commonProps}
+        ranges={[{ ...commonProps.ranges[0], endDate: null }]}
+        retainEndDateOnFirstSelection
+      />
+    );
+    const methodResult = instance.calcNewSelection(subDays(endDate, 10), true);
+    compareRanges(methodResult.range, {
+      startDate: subDays(endDate, 10),
+      endDate: null,
+    });
+  });
 });