@ngdoc directive
@name ngModelOptions
@restrict A
@priority 10

@description
This directive allows you to modify the behaviour of {@link ngModel} directives within your
application. You can specify an `ngModelOptions` directive on any element. All {@link ngModel}
directives will use the options of their nearest `ngModelOptions` ancestor.

The `ngModelOptions` settings are found by evaluating the value of the attribute directive as
an AngularJS expression. This expression should evaluate to an object, whose properties contain
the settings. For example: `<div ng-model-options="{ debounce: 100 }"`.

## Inheriting Options

You can specify that an `ngModelOptions` setting should be inherited from a parent `ngModelOptions`
directive by giving it the value of `"$inherit"`.
Then it will inherit that setting from the first `ngModelOptions` directive found by traversing up the
DOM tree. If there is no ancestor element containing an `ngModelOptions` directive then default settings
will be used.

For example given the following fragment of HTML


```html
<div ng-model-options="{ allowInvalid: true, debounce: 200 }">
<form ng-model-options="{ updateOn: 'blur', allowInvalid: '$inherit' }">
<input ng-model-options="{ updateOn: 'default', allowInvalid: '$inherit' }" />
</form>
</div>
```

the `input` element will have the following settings

```js
{ allowInvalid: true, updateOn: 'default', debounce: 0 }
```

Notice that the `debounce` setting was not inherited and used the default value instead.

You can specify that all undefined settings are automatically inherited from an ancestor by
including a property with key of `"*"` and value of `"$inherit"`.

For example given the following fragment of HTML


```html
<div ng-model-options="{ allowInvalid: true, debounce: 200 }">
<form ng-model-options="{ updateOn: 'blur', "*": '$inherit' }">
<input ng-model-options="{ updateOn: 'default', "*": '$inherit' }" />
</form>
</div>
```

the `input` element will have the following settings

```js
{ allowInvalid: true, updateOn: 'default', debounce: 200 }
```

Notice that the `debounce` setting now inherits the value from the outer `<div>` element.

If you are creating a reusable component then you should be careful when using `"*": "$inherit"`
since you may inadvertently inherit a setting in the future that changes the behavior of your component.


## Triggering and debouncing model updates

The `updateOn` and `debounce` properties allow you to specify a custom list of events that will
trigger a model update and/or a debouncing delay so that the actual update only takes place when
a timer expires; this timer will be reset after another change takes place.

Given the nature of `ngModelOptions`, the value displayed inside input fields in the view might
be different from the value in the actual model. This means that if you update the model you
should also invoke {@link ngModel.NgModelController#$rollbackViewValue} on the relevant input field in
order to make sure it is synchronized with the model and that any debounced action is canceled.

The easiest way to reference the control's {@link ngModel.NgModelController#$rollbackViewValue}
method is by making sure the input is placed inside a form that has a `name` attribute. This is
important because `form` controllers are published to the related scope under the name in their
`name` attribute.

Any pending changes will take place immediately when an enclosing form is submitted via the
`submit` event. Note that `ngClick` events will occur before the model is updated. Use `ngSubmit`
to have access to the updated model.

### Overriding immediate updates

The following example shows how to override immediate updates. Changes on the inputs within the
form will update the model only when the control loses focus (blur event). If `escape` key is
pressed while the input field is focused, the value is reset to the value in the current model.

<example name="ngModelOptions-directive-blur" module="optionsExample">
<file name="index.html">
<div ng-controller="ExampleController">
<form name="userForm">
<label>
Name:
<input type="text" name="userName"
ng-model="user.name"
ng-model-options="{ updateOn: 'blur' }"
ng-keyup="cancel($event)" />
</label><br />
<label>
Other data:
<input type="text" ng-model="user.data" />
</label><br />
</form>
<pre>user.name = <span ng-bind="user.name"></span></pre>
</div>
</file>
<file name="app.js">
angular.module('optionsExample', [])
.controller('ExampleController', ['$scope', function($scope) {
$scope.user = { name: 'say', data: '' };

$scope.cancel = function(e) {
if (e.keyCode === 27) {
$scope.userForm.userName.$rollbackViewValue();
}
};
}]);
</file>
<file name="protractor.js" type="protractor">
var model = element(by.binding('user.name'));
var input = element(by.model('user.name'));
var other = element(by.model('user.data'));

it('should allow custom events', function() {
input.sendKeys(' hello');
input.click();
expect(model.getText()).toEqual('say');
other.click();
expect(model.getText()).toEqual('say hello');
});

it('should $rollbackViewValue when model changes', function() {
input.sendKeys(' hello');
expect(input.getAttribute('value')).toEqual('say hello');
input.sendKeys(protractor.Key.ESCAPE);
expect(input.getAttribute('value')).toEqual('say');
other.click();
expect(model.getText()).toEqual('say');
});
</file>
</example>

### Debouncing updates

The next example shows how to debounce model changes. Model will be updated only 1 sec after last change.
If the `Clear` button is pressed, any debounced action is canceled and the value becomes empty.

<example name="ngModelOptions-directive-debounce" module="optionsExample">
<file name="index.html">
<div ng-controller="ExampleController">
<form name="userForm">
Name:
<input type="text" name="userName"
ng-model="user.name"
ng-model-options="{ debounce: 1000 }" />
<button ng-click="userForm.userName.$rollbackViewValue(); user.name=''">Clear</button><br />
</form>
<pre>user.name = <span ng-bind="user.name"></span></pre>
</div>
</file>
<file name="app.js">
angular.module('optionsExample', [])
.controller('ExampleController', ['$scope', function($scope) {
$scope.user = { name: 'say' };
}]);
</file>
</example>

### Default events, extra triggers, and catch-all debounce values

This example shows the relationship between "default" update events and
additional `updateOn` triggers.

`default` events are those that are bound to the control, and when fired, update the `$viewValue`
via {@link ngModel.NgModelController#$setViewValue $setViewValue}. Every event that is not listed
in `updateOn` is considered a "default" event, since different control types have different
default events.

The control in this example updates by "default", "click", and "blur", with different `debounce`
values. You can see that "click" doesn't have an individual `debounce` value -
therefore it uses the `*` debounce value.

There is also a button that calls {@link ngModel.NgModelController#$setViewValue $setViewValue}
directly with a "custom" event. Since "custom" is not defined in the `updateOn` list,
it is considered a "default" event and will update the
control if "default" is defined in `updateOn`, and will receive the "default" debounce value.
Note that this is just to illustrate how custom controls would possibly call `$setViewValue`.

You can change the `updateOn` and `debounce` configuration to test different scenarios. This
is done with {@link ngModel.NgModelController#$overrideModelOptions $overrideModelOptions}.

<example name="ngModelOptions-advanced" module="optionsExample">
<file name="index.html">
<model-update-demo></model-update-demo>
</file>
<file name="app.js">
angular.module('optionsExample', [])
.component('modelUpdateDemo', {
templateUrl: 'template.html',
controller: function() {
this.name = 'Chinua';

this.options = {
updateOn: 'default blur click',
debounce: {
default: 2000,
blur: 0,
'*': 1000
}
};

this.updateEvents = function() {
var eventList = this.options.updateOn.split(' ');
eventList.push('*');
var events = {};

for (var i = 0; i < eventList.length; i++) {
events[eventList[i]] = this.options.debounce[eventList[i]];
}

this.events = events;
};

this.updateOptions = function() {
var options = angular.extend(this.options, {
updateOn: Object.keys(this.events).join(' ').replace('*', ''),
debounce: this.events
});

this.form.input.$overrideModelOptions(options);
};

Initialize the event form
this.updateEvents();
}
});
</file>
<file name="template.html">
<form name="$ctrl.form">
Input: <input type="text" name="input" ng-model="$ctrl.name" ng-model-options="$ctrl.options" />
</form>
Model: <tt>{{$ctrl.name}}</tt>
<hr>
<button ng-click="$ctrl.form.input.$setViewValue('some value', 'custom')">Trigger setViewValue with 'some value' and 'custom' event</button>

<hr>
<form ng-submit="$ctrl.updateOptions()">
<b>updateOn</b><br>
<input type="text" ng-model="$ctrl.options.updateOn" ng-change="$ctrl.updateEvents()" ng-model-options="{debounce: 500}">

<table>
<tr>
<th>Option</th>
<th>Debounce value</th>
</tr>
<tr ng-repeat="(key, value) in $ctrl.events">
<td>{{key}}</td>
<td><input type="number" ng-model="$ctrl.events[key]" /></td>
</tr>
</table>

<br>
<input type="submit" value="Update options">
</form>
</file>
</example>


## Model updates and validation

The default behaviour in `ngModel` is that the model value is set to `undefined` when the
validation determines that the value is invalid. By setting the `allowInvalid` property to true,
the model will still be updated even if the value is invalid.


## Connecting to the scope

By setting the `getterSetter` property to true you are telling ngModel that the `ngModel` expression
on the scope refers to a "getter/setter" function rather than the value itself.

The following example shows how to bind to getter/setters:

<example name="ngModelOptions-directive-getter-setter" module="getterSetterExample">
<file name="index.html">
<div ng-controller="ExampleController">
<form name="userForm">
<label>
Name:
<input type="text" name="userName"
ng-model="user.name"
ng-model-options="{ getterSetter: true }" />
</label>
</form>
<pre>user.name = <span ng-bind="user.name()"></span></pre>
</div>
</file>
<file name="app.js">
angular.module('getterSetterExample', [])
.controller('ExampleController', ['$scope', function($scope) {
var _name = 'Brian';
$scope.user = {
name: function(newName) {
return angular.isDefined(newName) ? (_name = newName) : _name;
}
};
}]);
</file>
</example>


## Programmatically changing options

The `ngModelOptions` expression is only evaluated once when the directive is linked; it is not
watched for changes. However, it is possible to override the options on a single
{@link ngModel.NgModelController} instance with
{@link ngModel.NgModelController#$overrideModelOptions `NgModelController#$overrideModelOptions()`}.
See also the example for
{@link ngModelOptions#default-events-extra-triggers-and-catch-all-debounce-values
Default events, extra triggers, and catch-all debounce values}.


## Specifying timezones

You can specify the timezone that date/time input directives expect by providing its name in the
`timezone` property.


## Formatting the value of `time` and `datetime-local`

With the options `timeSecondsFormat` and `timeStripZeroSeconds` it is possible to adjust the value
that is displayed in the control. Note that browsers may apply their own formatting
in the user interface.

<example name="ngModelOptions-time-format" module="timeExample">
<file name="index.html">
<time-example></time-example>
</file>
<file name="script.js">
angular.module('timeExample', [])
.component('timeExample', {
templateUrl: 'timeExample.html',
controller: function() {
this.time = new Date(1970, 0, 1, 14, 57, 0);

this.options = {
timeSecondsFormat: 'ss',
timeStripZeroSeconds: true
};

this.optionChange = function() {
this.timeForm.timeFormatted.$overrideModelOptions(this.options);
this.time = new Date(this.time);
};
}
});
</file>
<file name="timeExample.html">
<form name="$ctrl.timeForm">
<strong>Default</strong>:
<input type="time" ng-model="$ctrl.time" step="any" /><br>
<strong>With options</strong>:
<input type="time" name="timeFormatted" ng-model="$ctrl.time" step="any" ng-model-options="$ctrl.options" />
<br>

Options:<br>
<code>timeSecondsFormat</code>:
<input
type="text"
ng-model="$ctrl.options.timeSecondsFormat"
ng-change="$ctrl.optionChange()">
<br>
<code>timeStripZeroSeconds</code>:
<input
type="checkbox"
ng-model="$ctrl.options.timeStripZeroSeconds"
ng-change="$ctrl.optionChange()">
</form>
</file>
</example>

@param {Object} ngModelOptions options to apply to {@link ngModel} directives on this element and
and its descendents.

**General options**:

- `updateOn`: string specifying which event should the input be bound to. You can set several
events using an space delimited list. There is a special event called `default` that
matches the default events belonging to the control. These are the events that are bound to
the control, and when fired, update the `$viewValue` via `$setViewValue`.

`ngModelOptions` considers every event that is not listed in `updateOn` a "default" event,
since different control types use different default events.

See also the section {@link ngModelOptions#triggering-and-debouncing-model-updates
Triggering and debouncing model updates}.

- `debounce`: integer value which contains the debounce model update value in milliseconds. A
value of 0 triggers an immediate update. If an object is supplied instead, you can specify a
custom value for each event. For example:
```
ng-model-options="{
updateOn: 'default blur',
debounce: { 'default': 500, 'blur': 0 }
}"
```
You can use the `*` key to specify a debounce value that applies to all events that are not
specifically listed. In the following example, `mouseup` would have a debounce delay of 1000:
```
ng-model-options="{
updateOn: 'default blur mouseup',
debounce: { 'default': 500, 'blur': 0, '*': 1000 }
}"
```
- `allowInvalid`: boolean value which indicates that the model can be set with values that did
not validate correctly instead of the default behavior of setting the model to undefined.
- `getterSetter`: boolean value which determines whether or not to treat functions bound to
`ngModel` as getters/setters.


**Input-type specific options**:

- `timezone`: Defines the timezone to be used to read/write the `Date` instance in the model for
`<input type="date" />`, `<input type="time" />`, ... . It understands UTC/GMT and the
continental US time zone abbreviations, but for general use, use a time zone offset, for
example, `'+0430'` (4 hours, 30 minutes east of the Greenwich meridian)
If not specified, the timezone of the browser will be used.
Note that changing the timezone will have no effect on the current date, and is only applied after
the next input / model change.

- `timeSecondsFormat`: Defines if the `time` and `datetime-local` types should show seconds and
milliseconds. The option follows the format string of {@link date date filter}.
By default, the options is `undefined` which is equal to `'ss.sss'` (seconds and milliseconds).
The other options are `'ss'` (strips milliseconds), and `''` (empty string), which strips both
seconds and milliseconds.
Note that browsers that support `time` and `datetime-local` require the hour and minutes
part of the time string, and may show the value differently in the user interface.
{@link ngModelOptions#formatting-the-value-of-time-and-datetime-local- See the example}.

- `timeStripZeroSeconds`: Defines if the `time` and `datetime-local` types should strip the
seconds and milliseconds from the formatted value if they are zero. This option is applied
after `timeSecondsFormat`.
This option can be used to make the formatting consistent over different browsers, as some
browsers with support for `time` will natively hide the milliseconds and
seconds if they are zero, but others won't, and browsers that don't implement these input
types will always show the full string.
{@link ngModelOptions#formatting-the-value-of-time-and-datetime-local- See the example}.
function() {
  NgModelOptionsController.$inject = ['$attrs', '$scope'];
  function NgModelOptionsController($attrs, $scope) {
    this.$$attrs = $attrs;
    this.$$scope = $scope;
  }
  NgModelOptionsController.prototype = {
    $onInit: function() {
      var parentOptions = this.parentCtrl ? this.parentCtrl.$options : defaultModelOptions;
      var modelOptionsDefinition = this.$$scope.$eval(this.$$attrs.ngModelOptions);

      this.$options = parentOptions.createChild(modelOptionsDefinition);
    }
  };

  return {
    restrict: 'A',
    // ngModelOptions needs to run before ngModel and input directives
    priority: 10,
    require: {parentCtrl: '?^^ngModelOptions'},
    bindToController: true,
    controller: NgModelOptionsController
  };
}