import { Observable } from '../Observable';
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import { Subscriber } from '../Subscriber';
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import { SchedulerLike } from '../types';
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import { isFunction } from '../util/isFunction';
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/**
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* Creates an observable that will create an error instance and push it to the consumer as an error
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* immediately upon subscription.
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*
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* <span class="informal">Just errors and does nothing else</span>
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*
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* 
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*
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* This creation function is useful for creating an observable that will create an error and error every
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* time it is subscribed to. Generally, inside of most operators when you might want to return an errored
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* observable, this is unnecessary. In most cases, such as in the inner return of {@link concatMap},
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* {@link mergeMap}, {@link defer}, and many others, you can simply throw the error, and RxJS will pick
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* that up and notify the consumer of the error.
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*
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* ## Example
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*
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* Create a simple observable that will create a new error with a timestamp and log it
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* and the message every time you subscribe to it
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*
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* ```ts
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* import { throwError } from 'rxjs';
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*
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* let errorCount = 0;
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*
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* const errorWithTimestamp$ = throwError(() => {
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* const error: any = new Error(`This is error number ${ ++errorCount }`);
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* error.timestamp = Date.now();
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* return error;
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* });
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*
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* errorWithTimestamp$.subscribe({
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* error: err => console.log(err.timestamp, err.message)
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* });
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*
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* errorWithTimestamp$.subscribe({
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* error: err => console.log(err.timestamp, err.message)
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* });
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*
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* // Logs the timestamp and a new error message for each subscription
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* ```
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*
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* ### Unnecessary usage
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*
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* Using `throwError` inside of an operator or creation function
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* with a callback, is usually not necessary
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*
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* ```ts
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* import { of, concatMap, timer, throwError } from 'rxjs';
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*
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* const delays$ = of(1000, 2000, Infinity, 3000);
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*
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* delays$.pipe(
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* concatMap(ms => {
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* if (ms < 10000) {
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* return timer(ms);
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* } else {
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* // This is probably overkill.
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* return throwError(() => new Error(`Invalid time ${ ms }`));
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* }
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* })
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* )
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* .subscribe({
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* next: console.log,
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* error: console.error
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* });
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* ```
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*
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* You can just throw the error instead
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*
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* ```ts
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* import { of, concatMap, timer } from 'rxjs';
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*
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* const delays$ = of(1000, 2000, Infinity, 3000);
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*
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* delays$.pipe(
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* concatMap(ms => {
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* if (ms < 10000) {
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* return timer(ms);
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* } else {
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* // Cleaner and easier to read for most folks.
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* throw new Error(`Invalid time ${ ms }`);
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* }
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* })
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* )
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* .subscribe({
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* next: console.log,
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* error: console.error
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* });
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* ```
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*
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* @param errorFactory A factory function that will create the error instance that is pushed.
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*/
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export function throwError(errorFactory: () => any): Observable<never>;
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/**
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* Returns an observable that will error with the specified error immediately upon subscription.
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*
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* @param error The error instance to emit
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* @deprecated Support for passing an error value will be removed in v8. Instead, pass a factory function to `throwError(() => new Error('test'))`. This is
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* because it will create the error at the moment it should be created and capture a more appropriate stack trace. If
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* for some reason you need to create the error ahead of time, you can still do that: `const err = new Error('test'); throwError(() => err);`.
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*/
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export function throwError(error: any): Observable<never>;
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/**
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* Notifies the consumer of an error using a given scheduler by scheduling it at delay `0` upon subscription.
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*
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* @param errorOrErrorFactory An error instance or error factory
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* @param scheduler A scheduler to use to schedule the error notification
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* @deprecated The `scheduler` parameter will be removed in v8.
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* Use `throwError` in combination with {@link observeOn}: `throwError(() => new Error('test')).pipe(observeOn(scheduler));`.
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* Details: https://rxjs.dev/deprecations/scheduler-argument
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*/
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export function throwError(errorOrErrorFactory: any, scheduler: SchedulerLike): Observable<never>;
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export function throwError(errorOrErrorFactory: any, scheduler?: SchedulerLike): Observable<never> {
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const errorFactory = isFunction(errorOrErrorFactory) ? errorOrErrorFactory : () => errorOrErrorFactory;
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const init = (subscriber: Subscriber<never>) => subscriber.error(errorFactory());
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return new Observable(scheduler ? (subscriber) => scheduler.schedule(init as any, 0, subscriber) : init);
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}
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