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259 lines
8.8 KiB
259 lines
8.8 KiB
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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