/**
 * @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 { OpaqueToken } from '@angular/core';
/**
 * A bridge between a control and a native element.
 *
 * A `ControlValueAccessor` abstracts the operations of writing a new value to a
 * DOM element representing an input control.
 *
 * Please see {@link DefaultValueAccessor} for more information.
 *
 * @experimental
 */
export interface ControlValueAccessor {
    /**
     * Write a new value to the element.
     */
    writeValue(obj: any): void;
    /**
     * Set the function to be called when the control receives a change event.
     */
    registerOnChange(fn: any): void;
    /**
     * Set the function to be called when the control receives a touch event.
     */
    registerOnTouched(fn: any): void;
}
/**
 * Used to provide a {@link ControlValueAccessor} for form controls.
 *
 * See {@link DefaultValueAccessor} for how to implement one.
 * @experimental
 */
export declare const NG_VALUE_ACCESSOR: OpaqueToken;