feat: onDateSelect callback functionality (#44)

README.md

@@ -203,6 +203,20 @@ datePicker(selector, options, {
   }
 });
 ```
+
+### onDateSelect
+
+A callback that accepts a Date object when a date is selected via the date picker.
+
+Using it in your code:
+```javascript
+datePicker(selector, options, {
+  onDateSelect: function(selectedDate) {
+    // do something with selected date
+  }
+});
+```
+
 ## Running locally
 
 Clone this repository to your local machine and install dependencies.

src/__tests__/datepicker.test.js

@@ -1059,5 +1059,30 @@ describe('Date picker', () => {
 
       expect(highlighted === document.activeElement).toBeTruthy();
     });
+
+    it('should call the onDateSelect callback with the selected date', () => {
+      let expectedDate;
+
+      datePicker(
+        document.querySelector('.date-picker'),
+        {},
+        {
+          onDateSelect: (date) => {
+            expectedDate = date;
+          },
+        },
+      );
+
+      const revealButton = document.querySelector('.date-picker__reveal');
+
+      $(revealButton).trigger('click');
+
+      const todayButton = document.querySelector(`[data-test-id="${today.toLocaleDateString()}"]`);
+      $(todayButton).trigger('click');
+
+      expect(expectedDate.getDate()).toEqual(today.getDate());
+      expect(expectedDate.getMonth()).toEqual(today.getMonth());
+      expect(expectedDate.getFullYear()).toEqual(today.getFullYear());
+    });
   });
 });

src/js/datepicker.js

@@ -166,6 +166,10 @@ function datePicker(datePickerElement, options = {}, callbacks = {}) {
     elements.inputs.day.value = formatDateInput(date.getDate());
     elements.inputs.month.value = formatDateInput(date.getMonth() + 1);
     elements.inputs.year.value = date.getFullYear();
+
+    if (callbacks.onDateSelect) {
+      callbacks.onDateSelect(date);
+    }
   }
 
   function setIsPreviousEnabled() {