/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {Directive, EventEmitter, Host, HostListener, Inject, Input, OnChanges, OnDestroy, Optional, Output, Self, SimpleChanges, forwardRef} from '@angular/core';
import {FormControl} from '../model';
import {NG_ASYNC_VALIDATORS, NG_VALIDATORS} from '../validators';
import {AbstractFormGroupDirective} from './abstract_form_group_directive';
import {ControlContainer} from './control_container';
import {ControlValueAccessor, NG_VALUE_ACCESSOR} from './control_value_accessor';
import {NgControl} from './ng_control';
import {NgForm} from './ng_form';
import {NgModelGroup} from './ng_model_group';
import {composeAsyncValidators, composeValidators, controlPath, isPropertyUpdated, selectValueAccessor, setUpControl} from './shared';
import {TemplateDrivenErrors} from './template_driven_errors';
import {AsyncValidator, AsyncValidatorFn, Validator, ValidatorFn} from './validators';
export const formControlBinding: any = {
provide: NgControl,
useExisting: forwardRef(() => NgModel)
};
/**
* `ngModel` forces an additional change detection run when its inputs change:
* E.g.:
* ```
*
{{myModel.valid}}
*
* ```
* I.e. `ngModel` can export itself on the element and then be used in the template.
* Normally, this would result in expressions before the `input` that use the exported directive
* to have and old value as they have been
* dirty checked before. As this is a very common case for `ngModel`, we added this second change
* detection run.
*
* Notes:
* - this is just one extra run no matter how many `ngModel` have been changed.
* - this is a general problem when using `exportAs` for directives!
*/
const resolvedPromise = Promise.resolve(null);
/**
* @whatItDoes Creates a {@link FormControl} instance from a domain model and binds it
* to a form control element.
*
* The {@link FormControl} instance will track the value, user interaction, and
* validation status of the control and keep the view synced with the model. If used
* within a parent form, the directive will also register itself with the form as a child
* control.
*
* @howToUse
*
* This directive can be used by itself or as part of a larger form. All you need is the
* `ngModel` selector to activate it.
*
* It accepts a domain model as an optional {@link @Input}. If you have a one-way binding
* to `ngModel` with `[]` syntax, changing the value of the domain model in the component
* class will set the value in the view. If you have a two-way binding with `[()]` syntax
* (also known as 'banana-box syntax'), the value in the UI will always be synced back to
* the domain model in your class as well.
*
* If you wish to inspect the properties of the associated {@link FormControl} (like
* validity state), you can also export the directive into a local template variable using
* `ngModel` as the key (ex: `#myVar="ngModel"`). You can then access the control using the
* directive's `control` property, but most properties you'll need (like `valid` and `dirty`)
* will fall through to the control anyway, so you can access them directly. You can see a
* full list of properties directly available in {@link AbstractControlDirective}.
*
* The following is an example of a simple standalone control using `ngModel`:
*
* {@example forms/ts/simpleNgModel/simple_ng_model_example.ts region='Component'}
*
* When using the `ngModel` within `