259 lines
8.8 KiB
JavaScript
259 lines
8.8 KiB
JavaScript
import { isFunction } from './util/isFunction';
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import { Subscription } from './Subscription';
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import { empty as emptyObserver } from './Observer';
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import { rxSubscriber as rxSubscriberSymbol } from './symbol/rxSubscriber';
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/**
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* Implements the {@link Observer} interface and extends the
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* {@link Subscription} class. While the {@link Observer} is the public API for
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* consuming the values of an {@link Observable}, all Observers get converted to
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* a Subscriber, in order to provide Subscription-like capabilities such as
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* `unsubscribe`. Subscriber is a common type in RxJS, and crucial for
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* implementing operators, but it is rarely used as a public API.
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*
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* @class Subscriber<T>
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*/
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export class Subscriber extends Subscription {
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/**
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* @param {Observer|function(value: T): void} [destinationOrNext] A partially
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* defined Observer or a `next` callback function.
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* @param {function(e: ?any): void} [error] The `error` callback of an
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* Observer.
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* @param {function(): void} [complete] The `complete` callback of an
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* Observer.
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*/
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constructor(destinationOrNext, error, complete) {
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super();
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this.syncErrorValue = null;
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this.syncErrorThrown = false;
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this.syncErrorThrowable = false;
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this.isStopped = false;
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switch (arguments.length) {
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case 0:
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this.destination = emptyObserver;
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break;
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case 1:
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if (!destinationOrNext) {
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this.destination = emptyObserver;
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break;
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}
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if (typeof destinationOrNext === 'object') {
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// HACK(benlesh): To resolve an issue where Node users may have multiple
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// copies of rxjs in their node_modules directory.
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if (isTrustedSubscriber(destinationOrNext)) {
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const trustedSubscriber = destinationOrNext[rxSubscriberSymbol]();
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this.syncErrorThrowable = trustedSubscriber.syncErrorThrowable;
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this.destination = trustedSubscriber;
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trustedSubscriber.add(this);
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}
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else {
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this.syncErrorThrowable = true;
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this.destination = new SafeSubscriber(this, destinationOrNext);
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}
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break;
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}
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default:
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this.syncErrorThrowable = true;
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this.destination = new SafeSubscriber(this, destinationOrNext, error, complete);
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break;
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}
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}
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[rxSubscriberSymbol]() { return this; }
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/**
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* A static factory for a Subscriber, given a (potentially partial) definition
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* of an Observer.
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* @param {function(x: ?T): void} [next] The `next` callback of an Observer.
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* @param {function(e: ?any): void} [error] The `error` callback of an
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* Observer.
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* @param {function(): void} [complete] The `complete` callback of an
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* Observer.
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* @return {Subscriber<T>} A Subscriber wrapping the (partially defined)
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* Observer represented by the given arguments.
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*/
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static create(next, error, complete) {
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const subscriber = new Subscriber(next, error, complete);
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subscriber.syncErrorThrowable = false;
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return subscriber;
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}
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/**
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* The {@link Observer} callback to receive notifications of type `next` from
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* the Observable, with a value. The Observable may call this method 0 or more
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* times.
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* @param {T} [value] The `next` value.
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* @return {void}
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*/
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next(value) {
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if (!this.isStopped) {
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this._next(value);
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}
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}
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/**
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* The {@link Observer} callback to receive notifications of type `error` from
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* the Observable, with an attached {@link Error}. Notifies the Observer that
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* the Observable has experienced an error condition.
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* @param {any} [err] The `error` exception.
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* @return {void}
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*/
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error(err) {
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if (!this.isStopped) {
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this.isStopped = true;
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this._error(err);
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}
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}
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/**
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* The {@link Observer} callback to receive a valueless notification of type
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* `complete` from the Observable. Notifies the Observer that the Observable
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* has finished sending push-based notifications.
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* @return {void}
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*/
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complete() {
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if (!this.isStopped) {
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this.isStopped = true;
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this._complete();
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}
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}
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unsubscribe() {
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if (this.closed) {
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return;
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}
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this.isStopped = true;
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super.unsubscribe();
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}
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_next(value) {
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this.destination.next(value);
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}
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_error(err) {
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this.destination.error(err);
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this.unsubscribe();
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}
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_complete() {
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this.destination.complete();
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this.unsubscribe();
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}
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/** @deprecated internal use only */ _unsubscribeAndRecycle() {
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const { _parent, _parents } = this;
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this._parent = null;
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this._parents = null;
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this.unsubscribe();
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this.closed = false;
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this.isStopped = false;
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this._parent = _parent;
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this._parents = _parents;
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return this;
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}
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}
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/**
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* We need this JSDoc comment for affecting ESDoc.
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* @ignore
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* @extends {Ignored}
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*/
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class SafeSubscriber extends Subscriber {
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constructor(_parentSubscriber, observerOrNext, error, complete) {
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super();
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this._parentSubscriber = _parentSubscriber;
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let next;
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let context = this;
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if (isFunction(observerOrNext)) {
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next = observerOrNext;
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}
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else if (observerOrNext) {
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next = observerOrNext.next;
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error = observerOrNext.error;
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complete = observerOrNext.complete;
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if (observerOrNext !== emptyObserver) {
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context = Object.create(observerOrNext);
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if (isFunction(context.unsubscribe)) {
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this.add(context.unsubscribe.bind(context));
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}
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context.unsubscribe = this.unsubscribe.bind(this);
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}
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}
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this._context = context;
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this._next = next;
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this._error = error;
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this._complete = complete;
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}
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next(value) {
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if (!this.isStopped && this._next) {
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const { _parentSubscriber } = this;
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if (!_parentSubscriber.syncErrorThrowable) {
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this.__tryOrUnsub(this._next, value);
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}
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else if (this.__tryOrSetError(_parentSubscriber, this._next, value)) {
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this.unsubscribe();
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}
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}
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}
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error(err) {
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if (!this.isStopped) {
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const { _parentSubscriber } = this;
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if (this._error) {
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if (!_parentSubscriber.syncErrorThrowable) {
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this.__tryOrUnsub(this._error, err);
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this.unsubscribe();
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}
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else {
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this.__tryOrSetError(_parentSubscriber, this._error, err);
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this.unsubscribe();
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}
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}
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else if (!_parentSubscriber.syncErrorThrowable) {
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this.unsubscribe();
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throw err;
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}
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else {
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_parentSubscriber.syncErrorValue = err;
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_parentSubscriber.syncErrorThrown = true;
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this.unsubscribe();
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}
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}
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}
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complete() {
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if (!this.isStopped) {
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const { _parentSubscriber } = this;
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if (this._complete) {
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const wrappedComplete = () => this._complete.call(this._context);
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if (!_parentSubscriber.syncErrorThrowable) {
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this.__tryOrUnsub(wrappedComplete);
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this.unsubscribe();
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}
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else {
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this.__tryOrSetError(_parentSubscriber, wrappedComplete);
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this.unsubscribe();
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}
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}
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else {
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this.unsubscribe();
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}
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}
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}
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__tryOrUnsub(fn, value) {
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try {
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fn.call(this._context, value);
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}
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catch (err) {
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this.unsubscribe();
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throw err;
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}
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}
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__tryOrSetError(parent, fn, value) {
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try {
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fn.call(this._context, value);
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}
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catch (err) {
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parent.syncErrorValue = err;
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parent.syncErrorThrown = true;
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return true;
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}
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return false;
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}
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/** @deprecated internal use only */ _unsubscribe() {
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const { _parentSubscriber } = this;
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this._context = null;
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this._parentSubscriber = null;
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_parentSubscriber.unsubscribe();
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}
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}
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function isTrustedSubscriber(obj) {
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return obj instanceof Subscriber || ('syncErrorThrowable' in obj && obj[rxSubscriberSymbol]);
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}
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//# sourceMappingURL=Subscriber.js.map
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