Fixing off by one error in DatePickerRange.

CHANGELOG.md

@@ -15,6 +15,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - [#923](https://github.com/plotly/dash-core-components/pull/923)
   Set autoComplete to off in `dcc.Dropdown`. This fixes [#808](https://github.com/plotly/dash-core-components/issues/808)
 
+### Fixed
+- [#930](https://github.com/plotly/dash-core-components/pull/930) Fixed a bug [#867](https://github.com/plotly/dash-core-components/issues/867) with `DatePickerRange` that would sometimes shift the allowed dates by one day.
+
 ## [1.15.0] - 2021-01-19
 ### Fixed
 - [#905](https://github.com/plotly/dash-core-components/pull/905) Make sure the `figure` prop of `dcc.Graph` receives updates from user interactions in the graph, by using the same `layout` object as provided in the prop rather than cloning it. Fixes [#879](https://github.com/plotly/dash-core-components/issues/879).

src/fragments/DatePickerRange.react.js

@@ -82,7 +82,10 @@ export default class DatePickerRange extends Component {
     }
 
     isOutsideRange(date) {
-        const {min_date_allowed, max_date_allowed} = this.props;
+        const {min_date_allowed, max_date_allowed} = convertToMoment(
+            this.props,
+            ['min_date_allowed', 'max_date_allowed']
+        );
 
         return (
             (min_date_allowed && date.isBefore(min_date_allowed)) ||

tests/integration/calendar/test_date_picker_range.py

@@ -80,3 +80,32 @@ def test_dtpr003_no_initial_month_no_min_date_start_date(dash_dcc):
         "#dps-initial-month .CalendarMonth.CalendarMonth_1[data-visible=true] strong",
         "August 2019",
     )
+
+
+def test_dtpr004_max_and_min_dates_are_clickable(dash_dcc):
+    app = dash.Dash(__name__)
+    app.layout = html.Div(
+        [
+            dcc.DatePickerRange(
+                id="dps-initial-month",
+                start_date=datetime(2021, 1, 11),
+                end_date=datetime(2021, 1, 19),
+                max_date_allowed=datetime(2021, 1, 20),
+                min_date_allowed=datetime(2021, 1, 10),
+            )
+        ]
+    )
+
+    dash_dcc.start_server(app)
+
+    dash_dcc.select_date_range("dps-initial-month", (10, 20))
+
+    dash_dcc.wait_for_text_to_equal(
+        '#dps-initial-month .DateInput_input.DateInput_input_1[placeholder="Start Date"]',
+        "01/10/2021",
+    )
+
+    dash_dcc.wait_for_text_to_equal(
+        '#dps-initial-month .DateInput_input.DateInput_input_1[placeholder="End Date"]',
+        "01/20/2021",
+    )