input.js

'use strict';

/* global

    -VALID_CLASS,
    -INVALID_CLASS,
    -PRISTINE_CLASS,
    -DIRTY_CLASS
*/

var URL_REGEXP = /^(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?$/;
var EMAIL_REGEXP = /^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,6}$/;
var NUMBER_REGEXP = /^\s*(\-|\+)?(\d+|(\d*(\.\d*)))\s*$/;
var DATE_REGEXP = /^(\d{4})-(\d{2})-(\d{2})$/;

var inputType = {

  /**
   * @ngdoc inputType
   * @name ng.directive:input.text
   *
   * @description
   * Standard HTML text input with angular data binding.
   *
   * @param {string} ngModel Assignable angular expression to data-bind to.
   * @param {string=} name Property name of the form under which the control is published.
   * @param {string=} required Adds `required` validation error key if the value is not entered.
   * @param {string=} ngRequired Adds `required` attribute and `required` validation constraint to
   *    the element when the ngRequired expression evaluates to true. Use `ngRequired` instead of
   *    `required` when you want to data-bind to the `required` attribute.
   * @param {number=} ngMinlength Sets `minlength` validation error key if the value is shorter than
   *    minlength.
   * @param {number=} ngMaxlength Sets `maxlength` validation error key if the value is longer than
   *    maxlength.
   * @param {string=} ngPattern Sets `pattern` validation error key if the value does not match the
   *    RegExp pattern expression. Expected value is `/regexp/` for inline patterns or `regexp` for
   *    patterns defined as scope expressions.
   * @param {string=} ngChange Angular expression to be executed when input changes due to user
   *    interaction with the input element.
   * @param {boolean=} [ngTrim=true] If set to false Angular will not automatically trim the input.
   *
   * @example
      <doc:example>
        <doc:source>
         <script>
           function Ctrl($scope) {
             $scope.text = 'guest';
             $scope.word = /^\s*\w*\s*$/;
           }
         </script>
         <form name="myForm" ng-controller="Ctrl">
           Single word: <input type="text" name="input" ng-model="text"
                               ng-pattern="word" required ng-trim="false">
           <span class="error" ng-show="myForm.input.$error.required">
             Required!</span>
           <span class="error" ng-show="myForm.input.$error.pattern">
             Single word only!</span>

           <tt>text = {{text}}</tt><br/>
           <tt>myForm.input.$valid = {{myForm.input.$valid}}</tt><br/>
           <tt>myForm.input.$error = {{myForm.input.$error}}</tt><br/>
           <tt>myForm.$valid = {{myForm.$valid}}</tt><br/>
           <tt>myForm.$error.required = {{!!myForm.$error.required}}</tt><br/>
          </form>
        </doc:source>
        <doc:scenario>
          it('should initialize to model', function() {
            expect(binding('text')).toEqual('guest');
            expect(binding('myForm.input.$valid')).toEqual('true');
          });

          it('should be invalid if empty', function() {
            input('text').enter('');
            expect(binding('text')).toEqual('');
            expect(binding('myForm.input.$valid')).toEqual('false');
          });

          it('should be invalid if multi word', function() {
            input('text').enter('hello world');
            expect(binding('myForm.input.$valid')).toEqual('false');
          });

          it('should not be trimmed', function() {
            input('text').enter('untrimmed ');
            expect(binding('text')).toEqual('untrimmed ');
            expect(binding('myForm.input.$valid')).toEqual('true');
          });
        </doc:scenario>
      </doc:example>
   */
  'text': textInputType,

    /**
     * @ngdoc inputType
     * @name ng.directive:input.date
     *
     * @description
     * HTML5 or text input with date validation and transformation. In browsers that do not yet support
     * the HTML5 date input, a text element will be used. The text must be entered in a valid ISO-8601
     * date format (yyyy-MM-dd), for example: `2009-01-06`. Will also accept a valid ISO date or Date object
     * as model input, but will always output a Date object to the model.
     *
     * @param {string} ngModel Assignable angular expression to data-bind to.
     * @param {string=} name Property name of the form under which the control is published.
     * @param {string=} min Sets the `min` validation error key if the value entered is less than `min`.
     * @param {string=} max Sets the `max` validation error key if the value entered is greater than `max`.
     * @param {string=} required Sets `required` validation error key if the value is not entered.
     * @param {string=} ngRequired Adds `required` attribute and `required` validation constraint to
     *    the element when the ngRequired expression evaluates to true. Use `ngRequired` instead of
     *    `required` when you want to data-bind to the `required` attribute.
     * @param {string=} ngChange Angular expression to be executed when input changes due to user
     *    interaction with the input element.
     *
     * @example
     <doc:example>
     <doc:source>
     <script>
        function Ctrl($scope) {
          $scope.value = '2013-10-22';
        }
     </script>
     <form name="myForm" ng-controller="Ctrl as dateCtrl">
        Pick a date between in 2013:
        <input type="date" name="input" ng-model="value"
            placeholder="yyyy-MM-dd" min="2013-01-01" max="2013-12-31" required />
        <span class="error" ng-show="myForm.input.$error.required">
            Required!</span>
        <span class="error" ng-show="myForm.input.$error.date">
            Not a valid date!</span>
         <tt>value = {{value}}</tt><br/>
         <tt>myForm.input.$valid = {{myForm.input.$valid}}</tt><br/>
         <tt>myForm.input.$error = {{myForm.input.$error}}</tt><br/>
         <tt>myForm.$valid = {{myForm.$valid}}</tt><br/>
         <tt>myForm.$error.required = {{!!myForm.$error.required}}</tt><br/>
     </form>
     </doc:source>
     <doc:scenario>
        it('should initialize to model', function() {
          expect(binding('value')).toEqual('2013-10-22');
          expect(binding('myForm.input.$valid')).toEqual('true');
        });

        it('should be invalid if empty', function() {
          input('value').enter('');
          expect(binding('value')).toEqual('');
          expect(binding('myForm.input.$valid')).toEqual('false');
        });

        it('should be invalid if over max', function() {
          input('value').enter('2015-01-01');
          expect(binding('value')).toEqual('');
          expect(binding('myForm.input.$valid')).toEqual('false');
        });
     </doc:scenario>
     </doc:example>
     */
  'date': dateInputType,

  /**
   * @ngdoc inputType
   * @name ng.directive:input.number
   *
   * @description
   * Text input with number validation and transformation. Sets the `number` validation
   * error if not a valid number.
   *
   * @param {string} ngModel Assignable angular expression to data-bind to.
   * @param {string=} name Property name of the form under which the control is published.
   * @param {string=} min Sets the `min` validation error key if the value entered is less than `min`.
   * @param {string=} max Sets the `max` validation error key if the value entered is greater than `max`.
   * @param {string=} required Sets `required` validation error key if the value is not entered.
   * @param {string=} ngRequired Adds `required` attribute and `required` validation constraint to
   *    the element when the ngRequired expression evaluates to true. Use `ngRequired` instead of
   *    `required` when you want to data-bind to the `required` attribute.
   * @param {number=} ngMinlength Sets `minlength` validation error key if the value is shorter than
   *    minlength.
   * @param {number=} ngMaxlength Sets `maxlength` validation error key if the value is longer than
   *    maxlength.
   * @param {string=} ngPattern Sets `pattern` validation error key if the value does not match the
   *    RegExp pattern expression. Expected value is `/regexp/` for inline patterns or `regexp` for
   *    patterns defined as scope expressions.
   * @param {string=} ngChange Angular expression to be executed when input changes due to user
   *    interaction with the input element.
   *
   * @example
      <doc:example>
        <doc:source>
         <script>
           function Ctrl($scope) {
             $scope.value = 12;
           }
         </script>
         <form name="myForm" ng-controller="Ctrl">
           Number: <input type="number" name="input" ng-model="value"
                          min="0" max="99" required>
           <span class="error" ng-show="myForm.input.$error.required">
             Required!</span>
           <span class="error" ng-show="myForm.input.$error.number">
             Not valid number!</span>
           <tt>value = {{value}}</tt><br/>
           <tt>myForm.input.$valid = {{myForm.input.$valid}}</tt><br/>
           <tt>myForm.input.$error = {{myForm.input.$error}}</tt><br/>
           <tt>myForm.$valid = {{myForm.$valid}}</tt><br/>
           <tt>myForm.$error.required = {{!!myForm.$error.required}}</tt><br/>
          </form>
        </doc:source>
        <doc:scenario>
          it('should initialize to model', function() {
           expect(binding('value')).toEqual('12');
           expect(binding('myForm.input.$valid')).toEqual('true');
          });

          it('should be invalid if empty', function() {
           input('value').enter('');
           expect(binding('value')).toEqual('');
           expect(binding('myForm.input.$valid')).toEqual('false');
          });

          it('should be invalid if over max', function() {
           input('value').enter('123');
           expect(binding('value')).toEqual('');
           expect(binding('myForm.input.$valid')).toEqual('false');
          });
        </doc:scenario>
      </doc:example>
   */
  'number': numberInputType,


  /**
   * @ngdoc inputType
   * @name ng.directive:input.url
   *
   * @description
   * Text input with URL validation. Sets the `url` validation error key if the content is not a
   * valid URL.
   *
   * @param {string} ngModel Assignable angular expression to data-bind to.
   * @param {string=} name Property name of the form under which the control is published.
   * @param {string=} required Sets `required` validation error key if the value is not entered.
   * @param {string=} ngRequired Adds `required` attribute and `required` validation constraint to
   *    the element when the ngRequired expression evaluates to true. Use `ngRequired` instead of
   *    `required` when you want to data-bind to the `required` attribute.
   * @param {number=} ngMinlength Sets `minlength` validation error key if the value is shorter than
   *    minlength.
   * @param {number=} ngMaxlength Sets `maxlength` validation error key if the value is longer than
   *    maxlength.
   * @param {string=} ngPattern Sets `pattern` validation error key if the value does not match the
   *    RegExp pattern expression. Expected value is `/regexp/` for inline patterns or `regexp` for
   *    patterns defined as scope expressions.
   * @param {string=} ngChange Angular expression to be executed when input changes due to user
   *    interaction with the input element.
   *
   * @example
      <doc:example>
        <doc:source>
         <script>
           function Ctrl($scope) {
             $scope.text = 'http://google.com';
           }
         </script>
         <form name="myForm" ng-controller="Ctrl">
           URL: <input type="url" name="input" ng-model="text" required>
           <span class="error" ng-show="myForm.input.$error.required">
             Required!</span>
           <span class="error" ng-show="myForm.input.$error.url">
             Not valid url!</span>
           <tt>text = {{text}}</tt><br/>
           <tt>myForm.input.$valid = {{myForm.input.$valid}}</tt><br/>
           <tt>myForm.input.$error = {{myForm.input.$error}}</tt><br/>
           <tt>myForm.$valid = {{myForm.$valid}}</tt><br/>
           <tt>myForm.$error.required = {{!!myForm.$error.required}}</tt><br/>
           <tt>myForm.$error.url = {{!!myForm.$error.url}}</tt><br/>
          </form>
        </doc:source>
        <doc:scenario>
          it('should initialize to model', function() {
            expect(binding('text')).toEqual('http://google.com');
            expect(binding('myForm.input.$valid')).toEqual('true');
          });

          it('should be invalid if empty', function() {
            input('text').enter('');
            expect(binding('text')).toEqual('');
            expect(binding('myForm.input.$valid')).toEqual('false');
          });

          it('should be invalid if not url', function() {
            input('text').enter('xxx');
            expect(binding('myForm.input.$valid')).toEqual('false');
          });
        </doc:scenario>
      </doc:example>
   */
  'url': urlInputType,


  /**
   * @ngdoc inputType
   * @name ng.directive:input.email
   *
   * @description
   * Text input with email validation. Sets the `email` validation error key if not a valid email
   * address.
   *
   * @param {string} ngModel Assignable angular expression to data-bind to.
   * @param {string=} name Property name of the form under which the control is published.
   * @param {string=} required Sets `required` validation error key if the value is not entered.
   * @param {string=} ngRequired Adds `required` attribute and `required` validation constraint to
   *    the element when the ngRequired expression evaluates to true. Use `ngRequired` instead of
   *    `required` when you want to data-bind to the `required` attribute.
   * @param {number=} ngMinlength Sets `minlength` validation error key if the value is shorter than
   *    minlength.
   * @param {number=} ngMaxlength Sets `maxlength` validation error key if the value is longer than
   *    maxlength.
   * @param {string=} ngPattern Sets `pattern` validation error key if the value does not match the
   *    RegExp pattern expression. Expected value is `/regexp/` for inline patterns or `regexp` for
   *    patterns defined as scope expressions.
   * @param {string=} ngChange Angular expression to be executed when input changes due to user
   *    interaction with the input element.
   *
   * @example
      <doc:example>
        <doc:source>
         <script>
           function Ctrl($scope) {
             $scope.text = 'me@example.com';
           }
         </script>
           <form name="myForm" ng-controller="Ctrl">
             Email: <input type="email" name="input" ng-model="text" required>
             <span class="error" ng-show="myForm.input.$error.required">
               Required!</span>
             <span class="error" ng-show="myForm.input.$error.email">
               Not valid email!</span>
             <tt>text = {{text}}</tt><br/>
             <tt>myForm.input.$valid = {{myForm.input.$valid}}</tt><br/>
             <tt>myForm.input.$error = {{myForm.input.$error}}</tt><br/>
             <tt>myForm.$valid = {{myForm.$valid}}</tt><br/>
             <tt>myForm.$error.required = {{!!myForm.$error.required}}</tt><br/>
             <tt>myForm.$error.email = {{!!myForm.$error.email}}</tt><br/>
           </form>
        </doc:source>
        <doc:scenario>
          it('should initialize to model', function() {
            expect(binding('text')).toEqual('me@example.com');
            expect(binding('myForm.input.$valid')).toEqual('true');
          });

          it('should be invalid if empty', function() {
            input('text').enter('');
            expect(binding('text')).toEqual('');
            expect(binding('myForm.input.$valid')).toEqual('false');
          });

          it('should be invalid if not email', function() {
            input('text').enter('xxx');
            expect(binding('myForm.input.$valid')).toEqual('false');
          });
        </doc:scenario>
      </doc:example>
   */
  'email': emailInputType,


  /**
   * @ngdoc inputType
   * @name ng.directive:input.radio
   *
   * @description
   * HTML radio button.
   *
   * @param {string} ngModel Assignable angular expression to data-bind to.
   * @param {string} value The value to which the expression should be set when selected.
   * @param {string=} name Property name of the form under which the control is published.
   * @param {string=} ngChange Angular expression to be executed when input changes due to user
   *    interaction with the input element.
   *
   * @example
      <doc:example>
        <doc:source>
         <script>
           function Ctrl($scope) {
             $scope.color = 'blue';
           }
         </script>
         <form name="myForm" ng-controller="Ctrl">
           <input type="radio" ng-model="color" value="red">  Red <br/>
           <input type="radio" ng-model="color" value="green"> Green <br/>
           <input type="radio" ng-model="color" value="blue"> Blue <br/>
           <tt>color = {{color}}</tt><br/>
          </form>
        </doc:source>
        <doc:scenario>
          it('should change state', function() {
            expect(binding('color')).toEqual('blue');

            input('color').select('red');
            expect(binding('color')).toEqual('red');
          });
        </doc:scenario>
      </doc:example>
   */
  'radio': radioInputType,


  /**
   * @ngdoc inputType
   * @name ng.directive:input.checkbox
   *
   * @description
   * HTML checkbox.
   *
   * @param {string} ngModel Assignable angular expression to data-bind to.
   * @param {string=} name Property name of the form under which the control is published.
   * @param {string=} ngTrueValue The value to which the expression should be set when selected.
   * @param {string=} ngFalseValue The value to which the expression should be set when not selected.
   * @param {string=} ngChange Angular expression to be executed when input changes due to user
   *    interaction with the input element.
   *
   * @example
      <doc:example>
        <doc:source>
         <script>
           function Ctrl($scope) {
             $scope.value1 = true;
             $scope.value2 = 'YES'
           }
         </script>
         <form name="myForm" ng-controller="Ctrl">
           Value1: <input type="checkbox" ng-model="value1"> <br/>
           Value2: <input type="checkbox" ng-model="value2"
                          ng-true-value="YES" ng-false-value="NO"> <br/>
           <tt>value1 = {{value1}}</tt><br/>
           <tt>value2 = {{value2}}</tt><br/>
          </form>
        </doc:source>
        <doc:scenario>
          it('should change state', function() {
            expect(binding('value1')).toEqual('true');
            expect(binding('value2')).toEqual('YES');

            input('value1').check();
            input('value2').check();
            expect(binding('value1')).toEqual('false');
            expect(binding('value2')).toEqual('NO');
          });
        </doc:scenario>
      </doc:example>
   */
  'checkbox': checkboxInputType,

  'hidden': noop,
  'button': noop,
  'submit': noop,
  'reset': noop
};

// A helper function to call $setValidity and return the value / undefined,
// a pattern that is repeated a lot in the input validation logic.
function validate(ctrl, validatorName, validity, value){
  ctrl.$setValidity(validatorName, validity);
  return validity ? value : undefined;
}

function textInputType(scope, element, attr, ctrl, $sniffer, $browser) {
  // In composition mode, users are still inputing intermediate text buffer,
  // hold the listener until composition is done.
  // More about composition events: https://developer.mozilla.org/en-US/docs/Web/API/CompositionEvent
  if (!$sniffer.android) {
    var composing = false;

    element.on('compositionstart', function(data) {
      composing = true;
    });

    element.on('compositionend', function() {
      composing = false;
    });
  }

  var listener = function() {
    if (composing) return;
    var value = element.val();

    // By default we will trim the value
    // If the attribute ng-trim exists we will avoid trimming
    // e.g. <input ng-model="foo" ng-trim="false">
    if (toBoolean(attr.ngTrim || 'T')) {
      value = trim(value);
    }

    if (ctrl.$viewValue !== value) {
      if (scope.$$phase) {
        ctrl.$setViewValue(value);
      } else {
        scope.$apply(function() {
          ctrl.$setViewValue(value);
        });
      }
    }
  };

  // if the browser does support "input" event, we are fine - except on IE9 which doesn't fire the
  // input event on backspace, delete or cut
  if ($sniffer.hasEvent('input')) {
    element.on('input', listener);
  } else {
    var timeout;

    var deferListener = function() {
      if (!timeout) {
        timeout = $browser.defer(function() {
          listener();
          timeout = null;
        });
      }
    };

    element.on('keydown', function(event) {
      var key = event.keyCode;

      // ignore
      //    command            modifiers                   arrows
      if (key === 91 || (15 < key && key < 19) || (37 <= key && key <= 40)) return;

      deferListener();
    });

    // if user modifies input value using context menu in IE, we need "paste" and "cut" events to catch it
    if ($sniffer.hasEvent('paste')) {
      element.on('paste cut', deferListener);
    }
  }

  // if user paste into input using mouse on older browser
  // or form autocomplete on newer browser, we need "change" event to catch it
  element.on('change', listener);

  ctrl.$render = function() {
    element.val(ctrl.$isEmpty(ctrl.$viewValue) ? '' : ctrl.$viewValue);
  };

  // pattern validator
  var pattern = attr.ngPattern,
      patternValidator,
      match;

  if (pattern) {
    var validateRegex = function(regexp, value) {
      return validate(ctrl, 'pattern', ctrl.$isEmpty(value) || regexp.test(value), value);
    };
    match = pattern.match(/^\/(.*)\/([gim]*)$/);
    if (match) {
      pattern = new RegExp(match[1], match[2]);
      patternValidator = function(value) {
        return validateRegex(pattern, value);
      };
    } else {
      patternValidator = function(value) {
        var patternObj = scope.$eval(pattern);

        if (!patternObj || !patternObj.test) {
          throw minErr('ngPattern')('noregexp',
            'Expected {0} to be a RegExp but was {1}. Element: {2}', pattern,
            patternObj, startingTag(element));
        }
        return validateRegex(patternObj, value);
      };
    }

    ctrl.$formatters.push(patternValidator);
    ctrl.$parsers.push(patternValidator);
  }

  // min length validator
  if (attr.ngMinlength) {
    var minlength = int(attr.ngMinlength);
    var minLengthValidator = function(value) {
      return validate(ctrl, 'minlength', ctrl.$isEmpty(value) || value.length >= minlength, value);
    };

    ctrl.$parsers.push(minLengthValidator);
    ctrl.$formatters.push(minLengthValidator);
  }

  // max length validator
  if (attr.ngMaxlength) {
    var maxlength = int(attr.ngMaxlength);
    var maxLengthValidator = function(value) {
      return validate(ctrl, 'maxlength', ctrl.$isEmpty(value) || value.length <= maxlength, value);
    };

    ctrl.$parsers.push(maxLengthValidator);
    ctrl.$formatters.push(maxLengthValidator);
  }
}

function dateInputType(scope, element, attr, ctrl, $sniffer, $browser) {
   textInputType(scope, element, attr, ctrl, $sniffer, $browser);

   ctrl.$parsers.push(function(value) {
      if(ctrl.$isEmpty(value)) {
         ctrl.$setValidity('date', true);
         return value;
      }

      if(DATE_REGEXP.test(value)) {
         ctrl.$setValidity('date', true);
         return new Date(getTime(value));
      }

      ctrl.$setValidity('date', false);
      return undefined;
   });

   ctrl.$formatters.push(function(value) {
       if(isDate(value)) {
           var year = value.getFullYear(),
               month = value.getMonth() + 1,
               day = value.getDate();

           month = (month < 10 ? '0' : '') + month;
           day = (day < 10 ? '0' : '') + day;
           return  year + '-' + month + '-' + day;
       }
       return ctrl.$isEmpty(value) ? '' : '' + value;
   });

   if(attr.min) {
      var minValidator = function(value) {
         var valid = ctrl.$isEmpty(value) ||
            (getTime(value) >= getTime(attr.min));
         ctrl.$setValidity('min', valid);
         return valid ? value : undefined;
      };

      ctrl.$parsers.push(minValidator);
      ctrl.$formatters.push(minValidator);
   }

   if(attr.max) {
      var maxValidator = function(value) {
         var valid = ctrl.$isEmpty(value) ||
            (getTime(value) <= getTime(attr.max));
         ctrl.$setValidity('max', valid);
         return valid ? value : undefined;
      };

      ctrl.$parsers.push(maxValidator);
      ctrl.$formatters.push(maxValidator);
   }

   function getTime(iso) {
      if(isDate(iso)) {
         return +iso;
      }

      if(isString(iso)) {
         DATE_REGEXP.lastIndex = 0;
         var parts = DATE_REGEXP.exec(iso),
            yyyy = +parts[1],
            mm = +parts[2] - 1,
            dd = +parts[3],
            time = new Date(yyyy, mm, dd);
         return +time;
      }

      return NaN;
   }
}

function numberInputType(scope, element, attr, ctrl, $sniffer, $browser) {
  textInputType(scope, element, attr, ctrl, $sniffer, $browser);

  ctrl.$parsers.push(function(value) {
    var empty = ctrl.$isEmpty(value);
    if (empty || NUMBER_REGEXP.test(value)) {
      ctrl.$setValidity('number', true);
      return value === '' ? null : (empty ? value : parseFloat(value));
    } else {
      ctrl.$setValidity('number', false);
      return undefined;
    }
  });

  ctrl.$formatters.push(function(value) {
    return ctrl.$isEmpty(value) ? '' : '' + value;
  });

  if (attr.min) {
    var minValidator = function(value) {
      var min = parseFloat(attr.min);
      return validate(ctrl, 'min', ctrl.$isEmpty(value) || value >= min, value);
    };

    ctrl.$parsers.push(minValidator);
    ctrl.$formatters.push(minValidator);
  }

  if (attr.max) {
    var maxValidator = function(value) {
      var max = parseFloat(attr.max);
      return validate(ctrl, 'max', ctrl.$isEmpty(value) || value <= max, value);
    };

    ctrl.$parsers.push(maxValidator);
    ctrl.$formatters.push(maxValidator);
  }

  ctrl.$formatters.push(function(value) {
    return validate(ctrl, 'number', ctrl.$isEmpty(value) || isNumber(value), value);
  });
}

function urlInputType(scope, element, attr, ctrl, $sniffer, $browser) {
  textInputType(scope, element, attr, ctrl, $sniffer, $browser);

  var urlValidator = function(value) {
    return validate(ctrl, 'url', ctrl.$isEmpty(value) || URL_REGEXP.test(value), value);
  };

  ctrl.$formatters.push(urlValidator);
  ctrl.$parsers.push(urlValidator);
}

function emailInputType(scope, element, attr, ctrl, $sniffer, $browser) {
  textInputType(scope, element, attr, ctrl, $sniffer, $browser);

  var emailValidator = function(value) {
    return validate(ctrl, 'email', ctrl.$isEmpty(value) || EMAIL_REGEXP.test(value), value);
  };

  ctrl.$formatters.push(emailValidator);
  ctrl.$parsers.push(emailValidator);
}

function radioInputType(scope, element, attr, ctrl) {
  // make the name unique, if not defined
  if (isUndefined(attr.name)) {
    element.attr('name', nextUid());
  }

  element.on('click', function() {
    if (element[0].checked) {
      scope.$apply(function() {
        ctrl.$setViewValue(attr.value);
      });
    }
  });

  ctrl.$render = function() {
    var value = attr.value;
    element[0].checked = (value == ctrl.$viewValue);
  };

  attr.$observe('value', ctrl.$render);
}

function checkboxInputType(scope, element, attr, ctrl) {
  var trueValue = attr.ngTrueValue,
      falseValue = attr.ngFalseValue;

  if (!isString(trueValue)) trueValue = true;
  if (!isString(falseValue)) falseValue = false;

  element.on('click', function() {
    scope.$apply(function() {
      ctrl.$setViewValue(element[0].checked);
    });
  });

  ctrl.$render = function() {
    element[0].checked = ctrl.$viewValue;
  };

  // Override the standard `$isEmpty` because a value of `false` means empty in a checkbox.
  ctrl.$isEmpty = function(value) {
    return value !== trueValue;
  };

  ctrl.$formatters.push(function(value) {
    return value === trueValue;
  });

  ctrl.$parsers.push(function(value) {
    return value ? trueValue : falseValue;
  });
}


/**
 * @ngdoc directive
 * @name ng.directive:textarea
 * @restrict E
 *
 * @description
 * HTML textarea element control with angular data-binding. The data-binding and validation
 * properties of this element are exactly the same as those of the
 * {@link ng.directive:input input element}.
 *
 * @param {string} ngModel Assignable angular expression to data-bind to.
 * @param {string=} name Property name of the form under which the control is published.
 * @param {string=} required Sets `required` validation error key if the value is not entered.
 * @param {string=} ngRequired Adds `required` attribute and `required` validation constraint to
 *    the element when the ngRequired expression evaluates to true. Use `ngRequired` instead of
 *    `required` when you want to data-bind to the `required` attribute.
 * @param {number=} ngMinlength Sets `minlength` validation error key if the value is shorter than
 *    minlength.
 * @param {number=} ngMaxlength Sets `maxlength` validation error key if the value is longer than
 *    maxlength.
 * @param {string=} ngPattern Sets `pattern` validation error key if the value does not match the
 *    RegExp pattern expression. Expected value is `/regexp/` for inline patterns or `regexp` for
 *    patterns defined as scope expressions.
 * @param {string=} ngChange Angular expression to be executed when input changes due to user
 *    interaction with the input element.
 */


/**
 * @ngdoc directive
 * @name ng.directive:input
 * @restrict E
 *
 * @description
 * HTML input element control with angular data-binding. Input control follows HTML5 input types
 * and polyfills the HTML5 validation behavior for older browsers.
 *
 * @param {string} ngModel Assignable angular expression to data-bind to.
 * @param {string=} name Property name of the form under which the control is published.
 * @param {string=} required Sets `required` validation error key if the value is not entered.
 * @param {boolean=} ngRequired Sets `required` attribute if set to true
 * @param {number=} ngMinlength Sets `minlength` validation error key if the value is shorter than
 *    minlength.
 * @param {number=} ngMaxlength Sets `maxlength` validation error key if the value is longer than
 *    maxlength.
 * @param {string=} ngPattern Sets `pattern` validation error key if the value does not match the
 *    RegExp pattern expression. Expected value is `/regexp/` for inline patterns or `regexp` for
 *    patterns defined as scope expressions.
 * @param {string=} ngChange Angular expression to be executed when input changes due to user
 *    interaction with the input element.
 *
 * @example
    <doc:example>
      <doc:source>
       <script>
         function Ctrl($scope) {
           $scope.user = {name: 'guest', last: 'visitor'};
         }
       </script>
       <div ng-controller="Ctrl">
         <form name="myForm">
           User name: <input type="text" name="userName" ng-model="user.name" required>
           <span class="error" ng-show="myForm.userName.$error.required">
             Required!</span><br>
           Last name: <input type="text" name="lastName" ng-model="user.last"
             ng-minlength="3" ng-maxlength="10">
           <span class="error" ng-show="myForm.lastName.$error.minlength">
             Too short!</span>
           <span class="error" ng-show="myForm.lastName.$error.maxlength">
             Too long!</span><br>
         </form>
         <hr>
         <tt>user = {{user}}</tt><br/>
         <tt>myForm.userName.$valid = {{myForm.userName.$valid}}</tt><br>
         <tt>myForm.userName.$error = {{myForm.userName.$error}}</tt><br>
         <tt>myForm.lastName.$valid = {{myForm.lastName.$valid}}</tt><br>
         <tt>myForm.lastName.$error = {{myForm.lastName.$error}}</tt><br>
         <tt>myForm.$valid = {{myForm.$valid}}</tt><br>
         <tt>myForm.$error.required = {{!!myForm.$error.required}}</tt><br>
         <tt>myForm.$error.minlength = {{!!myForm.$error.minlength}}</tt><br>
         <tt>myForm.$error.maxlength = {{!!myForm.$error.maxlength}}</tt><br>
       </div>
      </doc:source>
      <doc:scenario>
        it('should initialize to model', function() {
          expect(binding('user')).toEqual('{"name":"guest","last":"visitor"}');
          expect(binding('myForm.userName.$valid')).toEqual('true');
          expect(binding('myForm.$valid')).toEqual('true');
        });

        it('should be invalid if empty when required', function() {
          input('user.name').enter('');
          expect(binding('user')).toEqual('{"last":"visitor"}');
          expect(binding('myForm.userName.$valid')).toEqual('false');
          expect(binding('myForm.$valid')).toEqual('false');
        });

        it('should be valid if empty when min length is set', function() {
          input('user.last').enter('');
          expect(binding('user')).toEqual('{"name":"guest","last":""}');
          expect(binding('myForm.lastName.$valid')).toEqual('true');
          expect(binding('myForm.$valid')).toEqual('true');
        });

        it('should be invalid if less than required min length', function() {
          input('user.last').enter('xx');
          expect(binding('user')).toEqual('{"name":"guest"}');
          expect(binding('myForm.lastName.$valid')).toEqual('false');
          expect(binding('myForm.lastName.$error')).toMatch(/minlength/);
          expect(binding('myForm.$valid')).toEqual('false');
        });

        it('should be invalid if longer than max length', function() {
          input('user.last').enter('some ridiculously long name');
          expect(binding('user'))
            .toEqual('{"name":"guest"}');
          expect(binding('myForm.lastName.$valid')).toEqual('false');
          expect(binding('myForm.lastName.$error')).toMatch(/maxlength/);
          expect(binding('myForm.$valid')).toEqual('false');
        });
      </doc:scenario>
    </doc:example>
 */
var inputDirective = ['$browser', '$sniffer', function($browser, $sniffer) {
  return {
    restrict: 'E',
    require: '?ngModel',
    link: function(scope, element, attr, ctrl) {
      if (ctrl) {
        (inputType[lowercase(attr.type)] || inputType.text)(scope, element, attr, ctrl, $sniffer,
                                                            $browser);
      }
    }
  };
}];

var VALID_CLASS = 'ng-valid',
    INVALID_CLASS = 'ng-invalid',
    PRISTINE_CLASS = 'ng-pristine',
    DIRTY_CLASS = 'ng-dirty';

/**
 * @ngdoc object
 * @name ng.directive:ngModel.NgModelController
 *
 * @property {string} $viewValue Actual string value in the view.
 * @property {*} $modelValue The value in the model, that the control is bound to.
 * @property {Array.<Function>} $parsers Array of functions to execute, as a pipeline, whenever
       the control reads value from the DOM.  Each function is called, in turn, passing the value
       through to the next. Used to sanitize / convert the value as well as validation.
       For validation, the parsers should update the validity state using
       {@link ng.directive:ngModel.NgModelController#methods_$setValidity $setValidity()},
       and return `undefined` for invalid values.

 *
 * @property {Array.<Function>} $formatters Array of functions to execute, as a pipeline, whenever
       the model value changes. Each function is called, in turn, passing the value through to the
       next. Used to format / convert values for display in the control and validation.
 *      <pre>
 *      function formatter(value) {
 *        if (value) {
 *          return value.toUpperCase();
 *        }
 *      }
 *      ngModel.$formatters.push(formatter);
 *      </pre>
 *
 * @property {Array.<Function>} $viewChangeListeners Array of functions to execute whenever the
 *     view value has changed. It is called with no arguments, and its return value is ignored.
 *     This can be used in place of additional $watches against the model value.
 *
 * @property {Object} $error An object hash with all errors as keys.
 *
 * @property {boolean} $pristine True if user has not interacted with the control yet.
 * @property {boolean} $dirty True if user has already interacted with the control.
 * @property {boolean} $valid True if there is no error.
 * @property {boolean} $invalid True if at least one error on the control.
 *
 * @description
 *
 * `NgModelController` provides API for the `ng-model` directive. The controller contains
 * services for data-binding, validation, CSS updates, and value formatting and parsing. It
 * purposefully does not contain any logic which deals with DOM rendering or listening to
 * DOM events. Such DOM related logic should be provided by other directives which make use of
 * `NgModelController` for data-binding.
 *
 * ## Custom Control Example
 * This example shows how to use `NgModelController` with a custom control to achieve
 * data-binding. Notice how different directives (`contenteditable`, `ng-model`, and `required`)
 * collaborate together to achieve the desired result.
 *
 * Note that `contenteditable` is an HTML5 attribute, which tells the browser to let the element
 * contents be edited in place by the user.  This will not work on older browsers.
 *
 * <example module="customControl">
    <file name="style.css">
      [contenteditable] {
        border: 1px solid black;
        background-color: white;
        min-height: 20px;
      }

      .ng-invalid {
        border: 1px solid red;
      }

    </file>
    <file name="script.js">
      angular.module('customControl', []).
        directive('contenteditable', function() {
          return {
            restrict: 'A', // only activate on element attribute
            require: '?ngModel', // get a hold of NgModelController
            link: function(scope, element, attrs, ngModel) {
              if(!ngModel) return; // do nothing if no ng-model

              // Specify how UI should be updated
              ngModel.$render = function() {
                element.html(ngModel.$viewValue || '');
              };

              // Listen for change events to enable binding
              element.on('blur keyup change', function() {
                scope.$apply(read);
              });
              read(); // initialize

              // Write data to the model
              function read() {
                var html = element.html();
                // When we clear the content editable the browser leaves a <br> behind
                // If strip-br attribute is provided then we strip this out
                if( attrs.stripBr && html == '<br>' ) {
                  html = '';
                }
                ngModel.$setViewValue(html);
              }
            }
          };
        });
    </file>
    <file name="index.html">
      <form name="myForm">
       <div contenteditable
            name="myWidget" ng-model="userContent"
            strip-br="true"
            required>Change me!</div>
        <span ng-show="myForm.myWidget.$error.required">Required!</span>
       <hr>
       <textarea ng-model="userContent"></textarea>
      </form>
    </file>
    <file name="scenario.js">
      it('should data-bind and become invalid', function() {
        var contentEditable = element('[contenteditable]');

        expect(contentEditable.text()).toEqual('Change me!');
        input('userContent').enter('');
        expect(contentEditable.text()).toEqual('');
        expect(contentEditable.prop('className')).toMatch(/ng-invalid-required/);
      });
    </file>
 * </example>
 *
 *
 */
var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$parse',
    function($scope, $exceptionHandler, $attr, $element, $parse) {
  this.$viewValue = Number.NaN;
  this.$modelValue = Number.NaN;
  this.$parsers = [];
  this.$formatters = [];
  this.$viewChangeListeners = [];
  this.$pristine = true;
  this.$dirty = false;
  this.$valid = true;
  this.$invalid = false;
  this.$name = $attr.name;

  var ngModelGet = $parse($attr.ngModel),
      ngModelSet = ngModelGet.assign;

  if (!ngModelSet) {
    throw minErr('ngModel')('nonassign', "Expression '{0}' is non-assignable. Element: {1}",
        $attr.ngModel, startingTag($element));
  }

  /**
   * @ngdoc function
   * @name ng.directive:ngModel.NgModelController#$render
   * @methodOf ng.directive:ngModel.NgModelController
   *
   * @description
   * Called when the view needs to be updated. It is expected that the user of the ng-model
   * directive will implement this method.
   */
  this.$render = noop;

  /**
   * @ngdoc function
   * @name { ng.directive:ngModel.NgModelController#$isEmpty
   * @methodOf ng.directive:ngModel.NgModelController
   *
   * @description
   * This is called when we need to determine if the value of the input is empty.
   *
   * For instance, the required directive does this to work out if the input has data or not.
   * The default `$isEmpty` function checks whether the value is `undefined`, `''`, `null` or `NaN`.
   *
   * You can override this for input directives whose concept of being empty is different to the
   * default. The `checkboxInputType` directive does this because in its case a value of `false`
   * implies empty.
   */
  this.$isEmpty = function(value) {
    return isUndefined(value) || value === '' || value === null || value !== value;
  };

  var parentForm = $element.inheritedData('$formController') || nullFormCtrl,
      invalidCount = 0, // used to easily determine if we are valid
      $error = this.$error = {}; // keep invalid keys here


  // Setup initial state of the control
  $element.addClass(PRISTINE_CLASS);
  toggleValidCss(true);

  // convenience method for easy toggling of classes
  function toggleValidCss(isValid, validationErrorKey) {
    validationErrorKey = validationErrorKey ? '-' + snake_case(validationErrorKey, '-') : '';
    $element.
      removeClass((isValid ? INVALID_CLASS : VALID_CLASS) + validationErrorKey).
      addClass((isValid ? VALID_CLASS : INVALID_CLASS) + validationErrorKey);
  }

  /**
   * @ngdoc function
   * @name ng.directive:ngModel.NgModelController#$setValidity
   * @methodOf ng.directive:ngModel.NgModelController
   *
   * @description
   * Change the validity state, and notifies the form when the control changes validity. (i.e. it
   * does not notify form if given validator is already marked as invalid).
   *
   * This method should be called by validators - i.e. the parser or formatter functions.
   *
   * @param {string} validationErrorKey Name of the validator. the `validationErrorKey` will assign
   *        to `$error[validationErrorKey]=isValid` so that it is available for data-binding.
   *        The `validationErrorKey` should be in camelCase and will get converted into dash-case
   *        for class name. Example: `myError` will result in `ng-valid-my-error` and `ng-invalid-my-error`
   *        class and can be bound to as  `{{someForm.someControl.$error.myError}}` .
   * @param {boolean} isValid Whether the current state is valid (true) or invalid (false).
   */
  this.$setValidity = function(validationErrorKey, isValid) {
    // Purposeful use of ! here to cast isValid to boolean in case it is undefined
    // jshint -W018
    if ($error[validationErrorKey] === !isValid) return;
    // jshint +W018

    if (isValid) {
      if ($error[validationErrorKey]) invalidCount--;
      if (!invalidCount) {
        toggleValidCss(true);
        this.$valid = true;
        this.$invalid = false;
      }
    } else {
      toggleValidCss(false);
      this.$invalid = true;
      this.$valid = false;
      invalidCount++;
    }

    $error[validationErrorKey] = !isValid;
    toggleValidCss(isValid, validationErrorKey);

    parentForm.$setValidity(validationErrorKey, isValid, this);
  };

  /**
   * @ngdoc function
   * @name ng.directive:ngModel.NgModelController#$setPristine
   * @methodOf ng.directive:ngModel.NgModelController
   *
   * @description
   * Sets the control to its pristine state.
   *
   * This method can be called to remove the 'ng-dirty' class and set the control to its pristine
   * state (ng-pristine class).
   */
  this.$setPristine = function () {
    this.$dirty = false;
    this.$pristine = true;
    $element.removeClass(DIRTY_CLASS).addClass(PRISTINE_CLASS);
  };

  /**
   * @ngdoc function
   * @name ng.directive:ngModel.NgModelController#$setViewValue
   * @methodOf ng.directive:ngModel.NgModelController
   *
   * @description
   * Update the view value.
   *
   * This method should be called when the view value changes, typically from within a DOM event handler.
   * For example {@link ng.directive:input input} and
   * {@link ng.directive:select select} directives call it.
   *
   * It will update the $viewValue, then pass this value through each of the functions in `$parsers`,
   * which includes any validators. The value that comes out of this `$parsers` pipeline, be applied to
   * `$modelValue` and the **expression** specified in the `ng-model` attribute.
   *
   * Lastly, all the registered change listeners, in the `$viewChangeListeners` list, are called.
   *
   * Note that calling this function does not trigger a `$digest`.
   *
   * @param {string} value Value from the view.
   */
  this.$setViewValue = function(value) {
    this.$viewValue = value;

    // change to dirty
    if (this.$pristine) {
      this.$dirty = true;
      this.$pristine = false;
      $element.removeClass(PRISTINE_CLASS).addClass(DIRTY_CLASS);
      parentForm.$setDirty();
    }

    forEach(this.$parsers, function(fn) {
      value = fn(value);
    });

    if (this.$modelValue !== value) {
      this.$modelValue = value;
      ngModelSet($scope, value);
      forEach(this.$viewChangeListeners, function(listener) {
        try {
          listener();
        } catch(e) {
          $exceptionHandler(e);
        }
      });
    }
  };

  // model -> value
  var ctrl = this;

  $scope.$watch(function ngModelWatch() {
    var value = ngModelGet($scope);

    // if scope model value and ngModel value are out of sync
    if (ctrl.$modelValue !== value) {

      var formatters = ctrl.$formatters,
          idx = formatters.length;

      ctrl.$modelValue = value;
      while(idx--) {
        value = formatters[idx](value);
      }

      if (ctrl.$viewValue !== value) {
        ctrl.$viewValue = value;
        ctrl.$render();
      }
    }

    return value;
  });
}];


/**
 * @ngdoc directive
 * @name ng.directive:ngModel
 *
 * @element input
 *
 * @description
 * The `ngModel` directive binds an `input`,`select`, `textarea` (or custom form control) to a
 * property on the scope using {@link ng.directive:ngModel.NgModelController NgModelController},
 * which is created and exposed by this directive.
 *
 * `ngModel` is responsible for:
 *
 * - Binding the view into the model, which other directives such as `input`, `textarea` or `select`
 *   require.
 * - Providing validation behavior (i.e. required, number, email, url).
 * - Keeping the state of the control (valid/invalid, dirty/pristine, validation errors).
 * - Setting related css classes on the element (`ng-valid`, `ng-invalid`, `ng-dirty`, `ng-pristine`).
 * - Registering the control with its parent {@link ng.directive:form form}.
 *
 * Note: `ngModel` will try to bind to the property given by evaluating the expression on the
 * current scope. If the property doesn't already exist on this scope, it will be created
 * implicitly and added to the scope.
 *
 * For best practices on using `ngModel`, see:
 *
 *  - {@link https://github.com/angular/angular.js/wiki/Understanding-Scopes}
 *
 * For basic examples, how to use `ngModel`, see:
 *
 *  - {@link ng.directive:input input}
 *    - {@link ng.directive:input.text text}
 *    - {@link ng.directive:input.checkbox checkbox}
 *    - {@link ng.directive:input.radio radio}
 *    - {@link ng.directive:input.number number}
 *    - {@link ng.directive:input.email email}
 *    - {@link ng.directive:input.url url}
 *  - {@link ng.directive:select select}
 *  - {@link ng.directive:textarea textarea}
 *
 */
var ngModelDirective = function() {
  return {
    require: ['ngModel', '^?form'],
    controller: NgModelController,
    link: function(scope, element, attr, ctrls) {
      // notify others, especially parent forms

      var modelCtrl = ctrls[0],
          formCtrl = ctrls[1] || nullFormCtrl;

      formCtrl.$addControl(modelCtrl);

      scope.$on('$destroy', function() {
        formCtrl.$removeControl(modelCtrl);
      });
    }
  };
};


/**
 * @ngdoc directive
 * @name ng.directive:ngChange
 *
 * @description
 * Evaluate given expression when user changes the input.
 * The expression is not evaluated when the value change is coming from the model.
 *
 * Note, this directive requires `ngModel` to be present.
 *
 * @element input
 * @param {expression} ngChange {@link guide/expression Expression} to evaluate upon change
 * in input value.
 *
 * @example
 * <doc:example>
 *   <doc:source>
 *     <script>
 *       function Controller($scope) {
 *         $scope.counter = 0;
 *         $scope.change = function() {
 *           $scope.counter++;
 *         };
 *       }
 *     </script>
 *     <div ng-controller="Controller">
 *       <input type="checkbox" ng-model="confirmed" ng-change="change()" id="ng-change-example1" />
 *       <input type="checkbox" ng-model="confirmed" id="ng-change-example2" />
 *       <label for="ng-change-example2">Confirmed</label><br />
 *       debug = {{confirmed}}<br />
 *       counter = {{counter}}
 *     </div>
 *   </doc:source>
 *   <doc:scenario>
 *     it('should evaluate the expression if changing from view', function() {
 *       expect(binding('counter')).toEqual('0');
 *       element('#ng-change-example1').click();
 *       expect(binding('counter')).toEqual('1');
 *       expect(binding('confirmed')).toEqual('true');
 *     });
 *
 *     it('should not evaluate the expression if changing from model', function() {
 *       element('#ng-change-example2').click();
 *       expect(binding('counter')).toEqual('0');
 *       expect(binding('confirmed')).toEqual('true');
 *     });
 *   </doc:scenario>
 * </doc:example>
 */
var ngChangeDirective = valueFn({
  require: 'ngModel',
  link: function(scope, element, attr, ctrl) {
    ctrl.$viewChangeListeners.push(function() {
      scope.$eval(attr.ngChange);
    });
  }
});


var requiredDirective = function() {
  return {
    require: '?ngModel',
    link: function(scope, elm, attr, ctrl) {
      if (!ctrl) return;
      attr.required = true; // force truthy in case we are on non input element

      var validator = function(value) {
        if (attr.required && ctrl.$isEmpty(value)) {
          ctrl.$setValidity('required', false);
          return;
        } else {
          ctrl.$setValidity('required', true);
          return value;
        }
      };

      ctrl.$formatters.push(validator);
      ctrl.$parsers.unshift(validator);

      attr.$observe('required', function() {
        validator(ctrl.$viewValue);
      });
    }
  };
};


/**
 * @ngdoc directive
 * @name ng.directive:ngList
 *
 * @description
 * Text input that converts between a delimited string and an array of strings. The delimiter
 * can be a fixed string (by default a comma) or a regular expression.
 *
 * @element input
 * @param {string=} ngList optional delimiter that should be used to split the value. If
 *   specified in form `/something/` then the value will be converted into a regular expression.
 *
 * @example
    <doc:example>
      <doc:source>
       <script>
         function Ctrl($scope) {
           $scope.names = ['igor', 'misko', 'vojta'];
         }
       </script>
       <form name="myForm" ng-controller="Ctrl">
         List: <input name="namesInput" ng-model="names" ng-list required>
         <span class="error" ng-show="myForm.namesInput.$error.required">
           Required!</span>
         <br>
         <tt>names = {{names}}</tt><br/>
         <tt>myForm.namesInput.$valid = {{myForm.namesInput.$valid}}</tt><br/>
         <tt>myForm.namesInput.$error = {{myForm.namesInput.$error}}</tt><br/>
         <tt>myForm.$valid = {{myForm.$valid}}</tt><br/>
         <tt>myForm.$error.required = {{!!myForm.$error.required}}</tt><br/>
        </form>
      </doc:source>
      <doc:scenario>
        it('should initialize to model', function() {
          expect(binding('names')).toEqual('["igor","misko","vojta"]');
          expect(binding('myForm.namesInput.$valid')).toEqual('true');
          expect(element('span.error').css('display')).toBe('none');
        });

        it('should be invalid if empty', function() {
          input('names').enter('');
          expect(binding('names')).toEqual('');
          expect(binding('myForm.namesInput.$valid')).toEqual('false');
          expect(element('span.error').css('display')).not().toBe('none');
        });
      </doc:scenario>
    </doc:example>
 */
var ngListDirective = function() {
  return {
    require: 'ngModel',
    link: function(scope, element, attr, ctrl) {
      var match = /\/(.*)\//.exec(attr.ngList),
          separator = match && new RegExp(match[1]) || attr.ngList || ',';

      var parse = function(viewValue) {
        // If the viewValue is invalid (say required but empty) it will be `undefined`
        if (isUndefined(viewValue)) return;

        var list = [];

        if (viewValue) {
          forEach(viewValue.split(separator), function(value) {
            if (value) list.push(trim(value));
          });
        }

        return list;
      };

      ctrl.$parsers.push(parse);
      ctrl.$formatters.push(function(value) {
        if (isArray(value)) {
          return value.join(', ');
        }

        return undefined;
      });

      // Override the standard $isEmpty because an empty array means the input is empty.
      ctrl.$isEmpty = function(value) {
        return !value || !value.length;
      };
    }
  };
};


var CONSTANT_VALUE_REGEXP = /^(true|false|\d+)$/;
/**
 * @ngdoc directive
 * @name ng.directive:ngValue
 *
 * @description
 * Binds the given expression to the value of `input[select]` or `input[radio]`, so
 * that when the element is selected, the `ngModel` of that element is set to the
 * bound value.
 *
 * `ngValue` is useful when dynamically generating lists of radio buttons using `ng-repeat`, as
 * shown below.
 *
 * @element input
 * @param {string=} ngValue angular expression, whose value will be bound to the `value` attribute
 *   of the `input` element
 *
 * @example
    <doc:example>
      <doc:source>
       <script>
          function Ctrl($scope) {
            $scope.names = ['pizza', 'unicorns', 'robots'];
            $scope.my = { favorite: 'unicorns' };
          }
       </script>
        <form ng-controller="Ctrl">
          <h2>Which is your favorite?</h2>
            <label ng-repeat="name in names" for="{{name}}">
              {{name}}
              <input type="radio"
                     ng-model="my.favorite"
                     ng-value="name"
                     id="{{name}}"
                     name="favorite">
            </label>
          <div>You chose {{my.favorite}}</div>
        </form>
      </doc:source>
      <doc:scenario>
        it('should initialize to model', function() {
          expect(binding('my.favorite')).toEqual('unicorns');
        });
        it('should bind the values to the inputs', function() {
          input('my.favorite').select('pizza');
          expect(binding('my.favorite')).toEqual('pizza');
        });
      </doc:scenario>
    </doc:example>
 */
var ngValueDirective = function() {
  return {
    priority: 100,
    compile: function(tpl, tplAttr) {
      if (CONSTANT_VALUE_REGEXP.test(tplAttr.ngValue)) {
        return function ngValueConstantLink(scope, elm, attr) {
          attr.$set('value', scope.$eval(attr.ngValue));
        };
      } else {
        return function ngValueLink(scope, elm, attr) {
          scope.$watch(attr.ngValue, function valueWatchAction(value) {
            attr.$set('value', value);
          });
        };
      }
    }
  };
};