1import { SubscriptionLike, TeardownLogic } from './types';
2/**
3 * Represents a disposable resource, such as the execution of an Observable. A
4 * Subscription has one important method, `unsubscribe`, that takes no argument
5 * and just disposes the resource held by the subscription.
6 *
7 * Additionally, subscriptions may be grouped together through the `add()`
8 * method, which will attach a child Subscription to the current Subscription.
9 * When a Subscription is unsubscribed, all its children (and its grandchildren)
10 * will be unsubscribed as well.
11 *
12 * @class Subscription
13 */
14export declare class Subscription implements SubscriptionLike {
15    /** @nocollapse */
16    static EMPTY: Subscription;
17    /**
18     * A flag to indicate whether this Subscription has already been unsubscribed.
19     * @type {boolean}
20     */
21    closed: boolean;
22    /** @internal */
23    protected _parentOrParents: Subscription | Subscription[];
24    /** @internal */
25    private _subscriptions;
26    /**
27     * @param {function(): void} [unsubscribe] A function describing how to
28     * perform the disposal of resources when the `unsubscribe` method is called.
29     */
30    constructor(unsubscribe?: () => void);
31    /**
32     * Disposes the resources held by the subscription. May, for instance, cancel
33     * an ongoing Observable execution or cancel any other type of work that
34     * started when the Subscription was created.
35     * @return {void}
36     */
37    unsubscribe(): void;
38    /**
39     * Adds a tear down to be called during the unsubscribe() of this
40     * Subscription. Can also be used to add a child subscription.
41     *
42     * If the tear down being added is a subscription that is already
43     * unsubscribed, is the same reference `add` is being called on, or is
44     * `Subscription.EMPTY`, it will not be added.
45     *
46     * If this subscription is already in an `closed` state, the passed
47     * tear down logic will be executed immediately.
48     *
49     * When a parent subscription is unsubscribed, any child subscriptions that were added to it are also unsubscribed.
50     *
51     * @param {TeardownLogic} teardown The additional logic to execute on
52     * teardown.
53     * @return {Subscription} Returns the Subscription used or created to be
54     * added to the inner subscriptions list. This Subscription can be used with
55     * `remove()` to remove the passed teardown logic from the inner subscriptions
56     * list.
57     */
58    add(teardown: TeardownLogic): Subscription;
59    /**
60     * Removes a Subscription from the internal list of subscriptions that will
61     * unsubscribe during the unsubscribe process of this Subscription.
62     * @param {Subscription} subscription The subscription to remove.
63     * @return {void}
64     */
65    remove(subscription: Subscription): void;
66}
67