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import { Operator } from './Operator';
import { Observable } from './Observable';
import { Subscriber } from './Subscriber';
import { Subscription } from './Subscription';
import { Observer, SubscriptionLike, TeardownLogic } from './types';
import { ObjectUnsubscribedError } from './util/ObjectUnsubscribedError';
import { SubjectSubscription } from './SubjectSubscription';
import { rxSubscriber as rxSubscriberSymbol } from '../internal/symbol/rxSubscriber';
/**
* @class SubjectSubscriber<T>
*/
export class SubjectSubscriber<T> extends Subscriber<T> {
constructor(protected destination: Subject<T>) {
super(destination);
}
}
/**
* A Subject is a special type of Observable that allows values to be
* multicasted to many Observers. Subjects are like EventEmitters.
*
* Every Subject is an Observable and an Observer. You can subscribe to a
* Subject, and you can call next to feed values as well as error and complete.
*
* @class Subject<T>
*/
export class Subject<T> extends Observable<T> implements SubscriptionLike {
[rxSubscriberSymbol]() {
return new SubjectSubscriber(this);
}
observers: Observer<T>[] = [];
closed = false;
isStopped = false;
hasError = false;
thrownError: any = null;
constructor() {
super();
}
/**@nocollapse */
static create: Function = <T>(destination: Observer<T>, source: Observable<T>): AnonymousSubject<T> => {
return new AnonymousSubject<T>(destination, source);
}
lift<R>(operator: Operator<T, R>): Observable<R> {
const subject = new AnonymousSubject(this, this);
subject.operator = <any>operator;
return <any>subject;
}
next(value?: T) {
if (this.closed) {
throw new ObjectUnsubscribedError();
}
if (!this.isStopped) {
const { observers } = this;
const len = observers.length;
const copy = observers.slice();
for (let i = 0; i < len; i++) {
copy[i].next(value);
}
}
}
error(err: any) {
if (this.closed) {
throw new ObjectUnsubscribedError();
}
this.hasError = true;
this.thrownError = err;
this.isStopped = true;
const { observers } = this;
const len = observers.length;
const copy = observers.slice();
for (let i = 0; i < len; i++) {
copy[i].error(err);
}
this.observers.length = 0;
}
complete() {
if (this.closed) {
throw new ObjectUnsubscribedError();
}
this.isStopped = true;
const { observers } = this;
const len = observers.length;
const copy = observers.slice();
for (let i = 0; i < len; i++) {
copy[i].complete();
}
this.observers.length = 0;
}
unsubscribe() {
this.isStopped = true;
this.closed = true;
this.observers = null;
}
/** @deprecated This is an internal implementation detail, do not use. */
_trySubscribe(subscriber: Subscriber<T>): TeardownLogic {
if (this.closed) {
throw new ObjectUnsubscribedError();
} else {
return super._trySubscribe(subscriber);
}
}
/** @deprecated This is an internal implementation detail, do not use. */
_subscribe(subscriber: Subscriber<T>): Subscription {
if (this.closed) {
throw new ObjectUnsubscribedError();
} else if (this.hasError) {
subscriber.error(this.thrownError);
return Subscription.EMPTY;
} else if (this.isStopped) {
subscriber.complete();
return Subscription.EMPTY;
} else {
this.observers.push(subscriber);
return new SubjectSubscription(this, subscriber);
}
}
/**
* Creates a new Observable with this Subject as the source. You can do this
* to create customize Observer-side logic of the Subject and conceal it from
* code that uses the Observable.
* @return {Observable} Observable that the Subject casts to
*/
asObservable(): Observable<T> {
const observable = new Observable<T>();
(<any>observable).source = this;
return observable;
}
}
/**
* @class AnonymousSubject<T>
*/
export class AnonymousSubject<T> extends Subject<T> {
constructor(protected destination?: Observer<T>, source?: Observable<T>) {
super();
this.source = source;
}
next(value: T) {
const { destination } = this;
if (destination && destination.next) {
destination.next(value);
}
}
error(err: any) {
const { destination } = this;
if (destination && destination.error) {
this.destination.error(err);
}
}
complete() {
const { destination } = this;
if (destination && destination.complete) {
this.destination.complete();
}
}
/** @deprecated This is an internal implementation detail, do not use. */
_subscribe(subscriber: Subscriber<T>): Subscription {
const { source } = this;
if (source) {
return this.source.subscribe(subscriber);
} else {
return Subscription.EMPTY;
}
}
}