feat(ngOptions): add support for disabling an option

This patch adds support for disabling options based on model values. The
"disable when" syntax allows for listening to changes on those model values,
in order to dynamically enable and disable the options.

The changes prevent disabled options from being written to the selectCtrl
from the model. If a disabled selection is present on the model, normal
unknown or empty functionality kicks in.

Closes #638
Closes #11017

Author: sjbarker

src/ng/directive/ngOptions.js

@@ -94,15 +94,20 @@ var ngOptionsMinErr = minErr('ngOptions');
  *     * `label` **`for`** `value` **`in`** `array`
  *     * `select` **`as`** `label` **`for`** `value` **`in`** `array`
  *     * `label` **`group by`** `group` **`for`** `value` **`in`** `array`
+ *     * `label` **`disable when`** `disable` **`for`** `value` **`in`** `array`
  *     * `label` **`group by`** `group` **`for`** `value` **`in`** `array` **`track by`** `trackexpr`
+ *     * `label` **`disable when`** `disable` **`for`** `value` **`in`** `array` **`track by`** `trackexpr`
  *     * `label` **`for`** `value` **`in`** `array` | orderBy:`orderexpr` **`track by`** `trackexpr`
  *        (for including a filter with `track by`)
  *   * for object data sources:
  *     * `label` **`for (`**`key` **`,`** `value`**`) in`** `object`
  *     * `select` **`as`** `label` **`for (`**`key` **`,`** `value`**`) in`** `object`
  *     * `label` **`group by`** `group` **`for (`**`key`**`,`** `value`**`) in`** `object`
+ *     * `label` **`disable when`** `disable` **`for (`**`key`**`,`** `value`**`) in`** `object`
  *     * `select` **`as`** `label` **`group by`** `group`
  *         **`for` `(`**`key`**`,`** `value`**`) in`** `object`
+ *     * `select` **`as`** `label` **`disable when`** `disable`
+ *         **`for` `(`**`key`**`,`** `value`**`) in`** `object`
  *
  * Where:
  *
@@ -116,6 +121,8 @@ var ngOptionsMinErr = minErr('ngOptions');
  *      element. If not specified, `select` expression will default to `value`.
  *   * `group`: The result of this expression will be used to group options using the `<optgroup>`
  *      DOM element.
+ *   * `disable`: The result of this expression will be used to disable the rendered `<option>`
+ *      element. Return `true` to disable.
  *   * `trackexpr`: Used when working with an array of objects. The result of this expression will be
  *      used to identify the objects in the array. The `trackexpr` will most likely refer to the
  *     `value` variable (e.g. `value.propertyName`). With this the selection is preserved
@@ -129,10 +136,10 @@ var ngOptionsMinErr = minErr('ngOptions');
           .controller('ExampleController', ['$scope', function($scope) {
             $scope.colors = [
               {name:'black', shade:'dark'},
-              {name:'white', shade:'light'},
+              {name:'white', shade:'light', notAnOption: true},
               {name:'red', shade:'dark'},
-              {name:'blue', shade:'dark'},
-              {name:'yellow', shade:'light'}
+              {name:'blue', shade:'dark', notAnOption: true},
+              {name:'yellow', shade:'light', notAnOption: false}
             ];
             $scope.myColor = $scope.colors[2]; // red
           }]);
@@ -141,6 +148,7 @@ var ngOptionsMinErr = minErr('ngOptions');
           <ul>
             <li ng-repeat="color in colors">
               Name: <input ng-model="color.name">
+              <input type="checkbox" ng-model="color.notAnOption"> Disabled?
               [<a href ng-click="colors.splice($index, 1)">X</a>]
             </li>
             <li>
@@ -162,6 +170,12 @@ var ngOptionsMinErr = minErr('ngOptions');
           <select ng-model="myColor" ng-options="color.name group by color.shade for color in colors">
           </select><br/>
 
+          Color grouped by shade, with some disabled:
+          <select ng-model="myColor"
+                  ng-options="color.name group by color.shade disable when color.notAnOption for color in colors">
+          </select><br/>
+
+
 
           Select <a href ng-click="myColor = { name:'not in list', shade: 'other' }">bogus</a>.<br>
           <hr/>
@@ -186,16 +200,17 @@ var ngOptionsMinErr = minErr('ngOptions');
  */
 
 // jshint maxlen: false
-                         //000011111111110000000000022222222220000000000000000000003333333333000000000000004444444444444440000000005555555555555550000000666666666666666000000000000000777777777700000000000000000008888888888
-var NG_OPTIONS_REGEXP = /^\s*([\s\S]+?)(?:\s+as\s+([\s\S]+?))?(?:\s+group\s+by\s+([\s\S]+?))?\s+for\s+(?:([\$\w][\$\w]*)|(?:\(\s*([\$\w][\$\w]*)\s*,\s*([\$\w][\$\w]*)\s*\)))\s+in\s+([\s\S]+?)(?:\s+track\s+by\s+([\s\S]+?))?$/;
+//                     //00001111111111000000000002222222222000000000000000000000333333333300000000000000000000000004444444444400000000000005555555555555550000000006666666666666660000000777777777777777000000000000000888888888800000000000000000009999999999
+var NG_OPTIONS_REGEXP = /^\s*([\s\S]+?)(?:\s+as\s+([\s\S]+?))?(?:\s+group\s+by\s+([\s\S]+?))?(?:\s+disable\s+when\s+([\s\S]+?))?\s+for\s+(?:([\$\w][\$\w]*)|(?:\(\s*([\$\w][\$\w]*)\s*,\s*([\$\w][\$\w]*)\s*\)))\s+in\s+([\s\S]+?)(?:\s+track\s+by\s+([\s\S]+?))?$/;
                         // 1: value expression (valueFn)
                         // 2: label expression (displayFn)
                         // 3: group by expression (groupByFn)
-                        // 4: array item variable name
-                        // 5: object item key variable name
-                        // 6: object item value variable name
-                        // 7: collection expression
-                        // 8: track by expression
+                        // 4: disable when expression (disableWhenFn)
+                        // 5: array item variable name
+                        // 6: object item key variable name
+                        // 7: object item value variable name
+                        // 8: collection expression
+                        // 9: track by expression
 // jshint maxlen: 100
 
 
@@ -215,14 +230,14 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
     // Extract the parts from the ngOptions expression
 
     // The variable name for the value of the item in the collection
-    var valueName = match[4] || match[6];
+    var valueName = match[5] || match[7];
     // The variable name for the key of the item in the collection
-    var keyName = match[5];
+    var keyName = match[6];
 
     // An expression that generates the viewValue for an option if there is a label expression
     var selectAs = / as /.test(match[0]) && match[1];
     // An expression that is used to track the id of each object in the options collection
-    var trackBy = match[8];
+    var trackBy = match[9];
     // An expression that generates the viewValue for an option if there is no label expression
     var valueFn = $parse(match[2] ? match[1] : valueName);
     var selectAsFn = selectAs && $parse(selectAs);
@@ -237,7 +252,8 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
                               function getHashOfValue(viewValue) { return hashKey(viewValue); };
     var displayFn = $parse(match[2] || match[1]);
     var groupByFn = $parse(match[3] || '');
-    var valuesFn = $parse(match[7]);
+    var disableWhenFn = $parse(match[4] || '');
+    var valuesFn = $parse(match[8]);
 
     var locals = {};
     var getLocals = keyName ? function(value, key) {
@@ -250,11 +266,12 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
     };
 
 
-    function Option(selectValue, viewValue, label, group) {
+    function Option(selectValue, viewValue, label, group, disabled) {
       this.selectValue = selectValue;
       this.viewValue = viewValue;
       this.label = label;
       this.group = group;
+      this.disabled = disabled;
     }
 
     return {
@@ -275,6 +292,12 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
             var label = displayFn(scope, locals);
             watchedArray.push(label);
           }
+
+          // Only need to watch the disableWhenFn if there is a specific disable expression
+          if (match[4]) {
+            var disableWhen = disableWhenFn(scope, locals);
+            watchedArray.push(disableWhen);
+          }
         });
         return watchedArray;
       }),
@@ -300,7 +323,8 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
           var selectValue = getTrackByValue(viewValue, locals);
           var label = displayFn(scope, locals);
           var group = groupByFn(scope, locals);
-          var optionItem = new Option(selectValue, viewValue, label, group);
+          var disabled = disableWhenFn(scope, locals);
+          var optionItem = new Option(selectValue, viewValue, label, group, disabled);
 
           optionItems.push(optionItem);
           selectValueMap[selectValue] = optionItem;
@@ -326,7 +350,7 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
   return {
     restrict: 'A',
     terminal: true,
-    require: ['select', '?ngModel'],
+    require: ['select', 'ngModel'],
     link: function(scope, selectElement, attr, ctrls) {
 
       // if ngModel is not defined, we don't need to do anything
@@ -377,7 +401,7 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
       selectCtrl.writeValue = function writeNgOptionsValue(value) {
         var option = options.getOptionFromViewValue(value);
 
-        if (option) {
+        if (option && !option.disabled) {
           if (selectElement[0].value !== option.selectValue) {
             removeUnknownOption();
             removeEmptyOption();
@@ -401,7 +425,7 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
 
         var selectedOption = options.selectValueMap[selectElement.val()];
 
-        if (selectedOption) {
+        if (selectedOption && !selectedOption.disabled) {
           removeEmptyOption();
           removeUnknownOption();
           return selectedOption.viewValue;
@@ -426,18 +450,22 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
           if (value) {
             value.forEach(function(item) {
               var option = options.getOptionFromViewValue(item);
-              if (option) option.element.selected = true;
+              if (option && !option.disabled) option.element.selected = true;
             });
           }
         };
 
 
         selectCtrl.readValue = function readNgOptionsMultiple() {
-          var selectedValues = selectElement.val() || [];
-          return selectedValues.map(function(selectedKey) {
-            var option = options.selectValueMap[selectedKey];
-            return option.viewValue;
+          var selectedValues = selectElement.val() || [],
+              selections = [];
+
+          forEach(selectedValues, function(value) {
+            var option = options.selectValueMap[value];
+            if (!option.disabled) selections.push(option.viewValue);
           });
+
+          return selections;
         };
       }
 
@@ -470,6 +498,7 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
 
       function updateOptionElement(option, element) {
         option.element = element;
+        element.disabled = option.disabled;
         if (option.value !== element.value) element.value = option.selectValue;
         if (option.label !== element.label) {
           element.label = option.label;