feat(datepicker): predicate function to allow fine-grained control over pickable dates

src/components/datepicker/calendar.js

@@ -58,6 +58,7 @@
       scope: {
         minDate: '=mdMinDate',
         maxDate: '=mdMaxDate',
+        dateFilter: '=mdDateFilter',
       },
       require: ['ngModel', 'mdCalendar'],
       controller: CalendarCtrl,

src/components/datepicker/calendarMonth.js

@@ -124,8 +124,7 @@
 
       var cellText = this.dateLocale.dates[opt_date.getDate()];
 
-      if (this.dateUtil.isDateWithinRange(opt_date,
-          this.calendarCtrl.minDate, this.calendarCtrl.maxDate)) {
+      if (this.isDateEnabled(opt_date)) {
         // Add a indicator for select, hover, and focus states.
         var selectionIndicator = document.createElement('span');
         cell.appendChild(selectionIndicator);
@@ -145,7 +144,19 @@
 
     return cell;
   };
-
+
+  /**
+   * Check whether date is in range and enabled
+   * @param {Date=} opt_date
+   * @return {boolean} Whether the date is enabled.
+   */
+  CalendarMonthCtrl.prototype.isDateEnabled = function(opt_date) {
+    return this.dateUtil.isDateWithinRange(opt_date, 
+          this.calendarCtrl.minDate, this.calendarCtrl.maxDate) && 
+          (!angular.isFunction(this.calendarCtrl.dateFilter)
+           || this.calendarCtrl.dateFilter(opt_date));
+  }
+
   /**
    * Builds a `tr` element for the calendar grid.
    * @param rowNumber The week number within the month.

src/components/datepicker/datePicker.js

@@ -24,6 +24,7 @@
    * @param {expression=} ng-change Expression evaluated when the model value changes.
    * @param {Date=} md-min-date Expression representing a min date (inclusive).
    * @param {Date=} md-max-date Expression representing a max date (inclusive).
+   * @param {(function(Date): boolean)=} md-date-filter Function expecting a date and returning a boolean whether it can be selected or not.
    * @param {boolean=} disabled Whether the datepicker is disabled.
    * @param {boolean=} required Whether a value is required for the datepicker.
    *
@@ -75,6 +76,7 @@
             '<div class="md-datepicker-calendar">' +
               '<md-calendar role="dialog" aria-label="{{::ctrl.dateLocale.msgCalendar}}" ' +
                   'md-min-date="ctrl.minDate" md-max-date="ctrl.maxDate"' +
+                  'md-date-filter="ctrl.dateFilter"' +
                   'ng-model="ctrl.date" ng-if="ctrl.isCalendarOpen">' +
               '</md-calendar>' +
             '</div>' +
@@ -83,7 +85,8 @@
       scope: {
         minDate: '=mdMinDate',
         maxDate: '=mdMaxDate',
-        placeholder: '@mdPlaceholder'
+        placeholder: '@mdPlaceholder',
+        dateFilter: '=mdDateFilter'
       },
       controller: DatePickerCtrl,
       controllerAs: 'ctrl',
@@ -344,6 +347,10 @@
       if (this.dateUtil.isValidDate(this.maxDate)) {
         this.ngModelCtrl.$setValidity('maxdate', this.date <= this.maxDate);
       }
+
+      if (angular.isFunction(this.dateFilter)) {
+        this.ngModelCtrl.$setValidity('filtered', this.dateFilter(this.date));
+      }
     }
   };
 
@@ -365,8 +372,8 @@
       this.date = null;
       this.inputContainer.classList.remove(INVALID_CLASS);
     } else if (this.dateUtil.isValidDate(parsedDate) &&
-        this.dateLocale.isDateComplete(inputString) &&
-        this.dateUtil.isDateWithinRange(parsedDate, this.minDate, this.maxDate)) {
+        this.dateLocale.isDateComplete(inputString) && 
+        this.isDateEnabled(parsedDate)) {
       this.ngModelCtrl.$setViewValue(parsedDate);
       this.date = parsedDate;
       this.inputContainer.classList.remove(INVALID_CLASS);
@@ -375,7 +382,17 @@
       this.inputContainer.classList.toggle(INVALID_CLASS, inputString);
     }
   };
-
+
+  /**
+   * Check whether date is in range and enabled
+   * @param {Date=} opt_date
+   * @return {boolean} Whether the date is enabled.
+   */
+  DatePickerCtrl.prototype.isDateEnabled = function(opt_date) {
+    return this.dateUtil.isDateWithinRange(opt_date, this.minDate, this.maxDate) && 
+          (!angular.isFunction(this.dateFilter) || this.dateFilter(opt_date));
+  }
+
   /** Position and attach the floating calendar to the document. */
   DatePickerCtrl.prototype.attachCalendarPane = function() {
     var calendarPane = this.calendarPane;

src/components/datepicker/datePicker.spec.js

@@ -14,6 +14,7 @@ describe('md-date-picker', function() {
     '<md-datepicker name="birthday" ' +
          'md-max-date="maxDate" ' +
          'md-min-date="minDate" ' +
+         'md-date-filter="dateFilter"' +
          'ng-model="myDate" ' +
          'ng-required="isRequired" ' +
          'ng-disabled="isDisabled">' +
@@ -38,7 +39,6 @@ describe('md-date-picker', function() {
     createDatepickerInstance(DATEPICKER_TEMPLATE);
     controller.closeCalendarPane();
   }));
-
   /**
    * Compile and link the given template and store values for element, scope, and controller.
    * @param {string} template
@@ -149,6 +149,16 @@ describe('md-date-picker', function() {
 
         expect(formCtrl.$error['maxdate']).toBeTruthy();
       });
+
+      it('should set `filtered` $error flag on the form', function() {
+        pageScope.dateFilter = function(date) {
+          return date.getDay() === 1;
+        };
+        populateInputElement('2016-01-03');
+        controller.ngModelCtrl.$render();
+
+        expect(formCtrl.$error['filtered']).toBeTruthy();
+      });
     });
   });
 
@@ -186,6 +196,16 @@ describe('md-date-picker', function() {
       populateInputElement('7');
       expect(controller.inputContainer).toHaveClass('md-datepicker-invalid');
     });
+
+    it('should not update the model when value is not enabled', function() {
+      pageScope.dateFilter = function(date) {
+        return date.getDay() === 1;
+      };
+      pageScope.$apply();
+
+      populateInputElement('5/30/2014');
+      expect(controller.ngModelCtrl.$modelValue).toEqual(initialDate);
+    });
   });
 
   describe('floating calendar pane', function() {

src/components/datepicker/demoBasicUsage/index.html

@@ -10,17 +10,28 @@ <h4>Disabled date-picker</h4>
     <h4>Date-picker with min date and max date</h4>
     <md-datepicker ng-model="myDate" md-placeholder="Enter date"
         md-min-date="minDate" md-max-date="maxDate"></md-datepicker>
-
+    <h4>Only weekends are selectable</h4>
+    <md-datepicker ng-model="myDate" md-placeholder="Enter date"
+        md-date-filter="onlyWeekendsPredicate"></md-datepicker>
+
+    <h4>Only weekends within given range are selectable</h4>
+    <md-datepicker ng-model="myDate" md-placeholder="Enter date"
+        md-min-date="minDate" md-max-date="maxDate"
+        md-date-filter="onlyWeekendsPredicate"></md-datepicker>
+
     <h4>With ngMessages</h4>
     <form name="myForm">
       <md-datepicker name="dateField" ng-model="myDate" md-placeholder="Enter date"
-          required md-min-date="minDate" md-max-date="maxDate"></md-datepicker>
+          required md-min-date="minDate" md-max-date="maxDate"
+          md-date-filter="onlyWeekendsPredicate"></md-datepicker>
 
       <div class="validation-messages" ng-messages="myForm.dateField.$error">
         <div ng-message="required">This date is required!</div>
         <div ng-message="mindate">Date is too early!</div>
         <div ng-message="maxdate">Date is too late!</div>
+        <div ng-message="filtered">Only weekends are allowed!</div>
       </div>
     </form>
+
   </md-content>
 </div>

src/components/datepicker/demoBasicUsage/script.js

@@ -11,4 +11,9 @@ angular.module('datepickerBasicUsage',
       $scope.myDate.getFullYear(),
       $scope.myDate.getMonth() + 2,
       $scope.myDate.getDate());
+
+  $scope.onlyWeekendsPredicate = function(date) {
+    var day = date.getDay();
+    return day === 0 || day === 6;
+  }
 });