work.suroh.tk/node_modules/rxjs/_esm2015/Subscriber.js

259 lines
8.8 KiB
JavaScript

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