/**
 * The options object used to initialize an attached property.
 */
export interface IAttachedPropertyOptions<T, U> {
    /**
     * The human readable name for the property.
     *
     * #### Notes
     * By convention, this should be the same as the name used to define
     * the public accessor for the property value.
     *
     * This **does not** have an effect on the property lookup behavior.
     * Multiple properties may share the same name without conflict.
     */
    name: string;
    /**
     * The default value for the property.
     *
     * #### Notes
     * This value will be shared among all property owner instances. It
     * should be an immutable value unless a mutable shared singleton
     * is explicitly desired.
     *
     * If this is not provided, it defaults to `undefined`.
     */
    value?: U;
    /**
     * A factory function used to create the default property value.
     *
     * #### Notes
     * If provided, this takes precedence over the [[value]] option.
     *
     * This will be called whenever the property value is required,
     * but has not yet been set for a given owner.
     */
    create?: (owner: T) => U;
    /**
     * A function used to coerce a supplied value into the final value.
     *
     * #### Notes
     * This will be called whenever the property value is changed, or
     * when the property is explicitly coerced. The return value will
     * be used as the final value of the property.
     *
     * This will **not** be called for the initial default value.
     */
    coerce?: (owner: T, value: U) => U;
    /**
     * A function used to compare two values for equality.
     *
     * #### Notes
     * This is called to determine if the property value has changed.
     * It should return `true` if the given values are equivalent, or
     * `false` if they are different.
     *
     * If this is not provided, it defaults to the `===` operator.
     */
    compare?: (oldValue: U, newValue: U) => boolean;
    /**
     * A function called when the property value has changed.
     *
     * #### Notes
     * This will be invoked when the property value is changed and the
     * comparator indicates that the old value is not equal to the new
     * value.
     *
     * This will **not** be called for the initial default value.
     */
    changed?: (owner: T, oldValue: U, newValue: U) => void;
}
/**
 * A class which attaches a value to an external object.
 *
 * #### Notes
 * Attached properties are used to extend the state of an object with
 * semantic data from an unrelated class. They also encapsulate value
 * creation, coercion, and notification.
 *
 * Because attached property values are stored in a hash table, which
 * in turn is stored in a WeakMap keyed on the owner object, there is
 * non-trivial storage overhead involved in their use. The pattern is
 * therefore best used for the storage of rare data.
 */
export declare class AttachedProperty<T, U> {
    /**
     * Construct a new attached property.
     *
     * @param options - The options for initializing the property.
     */
    constructor(options: IAttachedPropertyOptions<T, U>);
    /**
     * Get the human readable name for the property.
     *
     * #### Notes
     * This is a read-only property.
     */
    readonly name: string;
    /**
     * Get the current value of the property for a given owner.
     *
     * @param owner - The property owner of interest.
     *
     * @returns The current value of the property.
     *
     * #### Notes
     * If the value has not yet been set, the default value will be
     * computed and assigned as the current value of the property.
     */
    get(owner: T): U;
    /**
     * Set the current value of the property for a given owner.
     *
     * @param owner - The property owner of interest.
     *
     * @param value - The value for the property.
     *
     * #### Notes
     * If the value has not yet been set, the default value will be
     * computed and used as the previous value for the comparison.
     */
    set(owner: T, value: U): void;
    /**
     * Explicitly coerce the current property value for a given owner.
     *
     * @param owner - The property owner of interest.
     *
     * #### Notes
     * If the value has not yet been set, the default value will be
     * computed and used as the previous value for the comparison.
     */
    coerce(owner: T): void;
    /**
     * Get or create the default value for the given owner.
     */
    private _createValue(owner);
    /**
     * Coerce the value for the given owner.
     */
    private _coerceValue(owner, value);
    /**
     * Compare the old value and new value for equality.
     */
    private _compareValue(oldValue, newValue);
    /**
     * Run the change notification if the given values are different.
     */
    private _maybeNotify(owner, oldValue, newValue);
    private _value;
    private _name;
    private _pid;
    private _create;
    private _coerce;
    private _compare;
    private _changed;
}
/**
 * Clear the stored property data for the given property owner.
 *
 * @param owner - The property owner of interest.
 *
 * #### Notes
 * This will clear all property values for the owner, but it will
 * **not** run the change notification for any of the properties.
 */
export declare function clearPropertyData(owner: any): void;