import { type Box } from './Box.js';
import { type ObservableCallback } from './ObservableCallback.js';
/**
 * An aggregate helper class for widgets that contain a variable with a
 * specified type which is intended to be controlled by the user.
 *
 * Useful for implementing widgets such as sliders, checkboxes, text input,
 * etc...
 *
 * @typeParam V - The type of {@link Variable#value}.
 *
 * @category State Management
 */
export declare class Variable<V> implements Box<V> {
    /** The current value, for internal use. */
    private _value;
    /** The function callbacks called when the value is changed */
    private callbacks;
    /**
     * @param initialValue - The initial value of this variable. Sets {@link Variable#_value}.
     */
    constructor(initialValue: V);
    /**
     * The current value.
     *
     * If setting, {@link Variable#setValue} is called with no group.
     */
    get value(): V;
    set value(value: V);
    watch(callback: ObservableCallback<V>, callNow?: boolean, group?: unknown): this;
    unwatch(callback: ObservableCallback<V>): this;
    setValue(value: V, group?: unknown): boolean;
    private doCallback;
}