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- import { Connectable, ObservableInput, SubjectLike } from '../types';
- import { Subject } from '../Subject';
- import { Subscription } from '../Subscription';
- import { Observable } from '../Observable';
- import { defer } from './defer';
- export interface ConnectableConfig<T> {
- /**
- * A factory function used to create the Subject through which the source
- * is multicast. By default this creates a {@link Subject}.
- */
- connector: () => SubjectLike<T>;
- /**
- * If true, the resulting observable will reset internal state upon disconnection
- * and return to a "cold" state. This allows the resulting observable to be
- * reconnected.
- * If false, upon disconnection, the connecting subject will remain the
- * connecting subject, meaning the resulting observable will not go "cold" again,
- * and subsequent repeats or resubscriptions will resubscribe to that same subject.
- */
- resetOnDisconnect?: boolean;
- }
- /**
- * The default configuration for `connectable`.
- */
- const DEFAULT_CONFIG: ConnectableConfig<unknown> = {
- connector: () => new Subject<unknown>(),
- resetOnDisconnect: true,
- };
- /**
- * Creates an observable that multicasts once `connect()` is called on it.
- *
- * @param source The observable source to make connectable.
- * @param config The configuration object for `connectable`.
- * @returns A "connectable" observable, that has a `connect()` method, that you must call to
- * connect the source to all consumers through the subject provided as the connector.
- */
- export function connectable<T>(source: ObservableInput<T>, config: ConnectableConfig<T> = DEFAULT_CONFIG): Connectable<T> {
- // The subscription representing the connection.
- let connection: Subscription | null = null;
- const { connector, resetOnDisconnect = true } = config;
- let subject = connector();
- const result: any = new Observable<T>((subscriber) => {
- return subject.subscribe(subscriber);
- });
- // Define the `connect` function. This is what users must call
- // in order to "connect" the source to the subject that is
- // multicasting it.
- result.connect = () => {
- if (!connection || connection.closed) {
- connection = defer(() => source).subscribe(subject);
- if (resetOnDisconnect) {
- connection.add(() => (subject = connector()));
- }
- }
- return connection;
- };
- return result;
- }
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