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- import { asyncScheduler } from '../scheduler/async';
- import { MonoTypeOperatorFunction, SchedulerLike, OperatorFunction, ObservableInput, ObservedValueOf } from '../types';
- import { isValidDate } from '../util/isDate';
- import { Subscription } from '../Subscription';
- import { operate } from '../util/lift';
- import { Observable } from '../Observable';
- import { innerFrom } from '../observable/innerFrom';
- import { createErrorClass } from '../util/createErrorClass';
- import { createOperatorSubscriber } from './OperatorSubscriber';
- import { executeSchedule } from '../util/executeSchedule';
- export interface TimeoutConfig<T, O extends ObservableInput<unknown> = ObservableInput<T>, M = unknown> {
- /**
- * The time allowed between values from the source before timeout is triggered.
- */
- each?: number;
- /**
- * The relative time as a `number` in milliseconds, or a specific time as a `Date` object,
- * by which the first value must arrive from the source before timeout is triggered.
- */
- first?: number | Date;
- /**
- * The scheduler to use with time-related operations within this operator. Defaults to {@link asyncScheduler}
- */
- scheduler?: SchedulerLike;
- /**
- * A factory used to create observable to switch to when timeout occurs. Provides
- * a {@link TimeoutInfo} about the source observable's emissions and what delay or
- * exact time triggered the timeout.
- */
- with?: (info: TimeoutInfo<T, M>) => O;
- /**
- * Optional additional metadata you can provide to code that handles
- * the timeout, will be provided through the {@link TimeoutError}.
- * This can be used to help identify the source of a timeout or pass along
- * other information related to the timeout.
- */
- meta?: M;
- }
- export interface TimeoutInfo<T, M = unknown> {
- /** Optional metadata that was provided to the timeout configuration. */
- readonly meta: M;
- /** The number of messages seen before the timeout */
- readonly seen: number;
- /** The last message seen */
- readonly lastValue: T | null;
- }
- /**
- * An error emitted when a timeout occurs.
- */
- export interface TimeoutError<T = unknown, M = unknown> extends Error {
- /**
- * The information provided to the error by the timeout
- * operation that created the error. Will be `null` if
- * used directly in non-RxJS code with an empty constructor.
- * (Note that using this constructor directly is not recommended,
- * you should create your own errors)
- */
- info: TimeoutInfo<T, M> | null;
- }
- export interface TimeoutErrorCtor {
- /**
- * @deprecated Internal implementation detail. Do not construct error instances.
- * Cannot be tagged as internal: https://github.com/ReactiveX/rxjs/issues/6269
- */
- new <T = unknown, M = unknown>(info?: TimeoutInfo<T, M>): TimeoutError<T, M>;
- }
- /**
- * An error thrown by the {@link timeout} operator.
- *
- * Provided so users can use as a type and do quality comparisons.
- * We recommend you do not subclass this or create instances of this class directly.
- * If you have need of a error representing a timeout, you should
- * create your own error class and use that.
- *
- * @see {@link timeout}
- */
- export const TimeoutError: TimeoutErrorCtor = createErrorClass(
- (_super) =>
- function TimeoutErrorImpl(this: any, info: TimeoutInfo<any> | null = null) {
- _super(this);
- this.message = 'Timeout has occurred';
- this.name = 'TimeoutError';
- this.info = info;
- }
- );
- /**
- * If `with` is provided, this will return an observable that will switch to a different observable if the source
- * does not push values within the specified time parameters.
- *
- * <span class="informal">The most flexible option for creating a timeout behavior.</span>
- *
- * The first thing to know about the configuration is if you do not provide a `with` property to the configuration,
- * when timeout conditions are met, this operator will emit a {@link TimeoutError}. Otherwise, it will use the factory
- * function provided by `with`, and switch your subscription to the result of that. Timeout conditions are provided by
- * the settings in `first` and `each`.
- *
- * The `first` property can be either a `Date` for a specific time, a `number` for a time period relative to the
- * point of subscription, or it can be skipped. This property is to check timeout conditions for the arrival of
- * the first value from the source _only_. The timings of all subsequent values from the source will be checked
- * against the time period provided by `each`, if it was provided.
- *
- * The `each` property can be either a `number` or skipped. If a value for `each` is provided, it represents the amount of
- * time the resulting observable will wait between the arrival of values from the source before timing out. Note that if
- * `first` is _not_ provided, the value from `each` will be used to check timeout conditions for the arrival of the first
- * value and all subsequent values. If `first` _is_ provided, `each` will only be use to check all values after the first.
- *
- * ## Examples
- *
- * Emit a custom error if there is too much time between values
- *
- * ```ts
- * import { interval, timeout, throwError } from 'rxjs';
- *
- * class CustomTimeoutError extends Error {
- * constructor() {
- * super('It was too slow');
- * this.name = 'CustomTimeoutError';
- * }
- * }
- *
- * const slow$ = interval(900);
- *
- * slow$.pipe(
- * timeout({
- * each: 1000,
- * with: () => throwError(() => new CustomTimeoutError())
- * })
- * )
- * .subscribe({
- * error: console.error
- * });
- * ```
- *
- * Switch to a faster observable if your source is slow.
- *
- * ```ts
- * import { interval, timeout } from 'rxjs';
- *
- * const slow$ = interval(900);
- * const fast$ = interval(500);
- *
- * slow$.pipe(
- * timeout({
- * each: 1000,
- * with: () => fast$,
- * })
- * )
- * .subscribe(console.log);
- * ```
- * @param config The configuration for the timeout.
- */
- export function timeout<T, O extends ObservableInput<unknown>, M = unknown>(
- config: TimeoutConfig<T, O, M> & { with: (info: TimeoutInfo<T, M>) => O }
- ): OperatorFunction<T, T | ObservedValueOf<O>>;
- /**
- * Returns an observable that will error or switch to a different observable if the source does not push values
- * within the specified time parameters.
- *
- * <span class="informal">The most flexible option for creating a timeout behavior.</span>
- *
- * The first thing to know about the configuration is if you do not provide a `with` property to the configuration,
- * when timeout conditions are met, this operator will emit a {@link TimeoutError}. Otherwise, it will use the factory
- * function provided by `with`, and switch your subscription to the result of that. Timeout conditions are provided by
- * the settings in `first` and `each`.
- *
- * The `first` property can be either a `Date` for a specific time, a `number` for a time period relative to the
- * point of subscription, or it can be skipped. This property is to check timeout conditions for the arrival of
- * the first value from the source _only_. The timings of all subsequent values from the source will be checked
- * against the time period provided by `each`, if it was provided.
- *
- * The `each` property can be either a `number` or skipped. If a value for `each` is provided, it represents the amount of
- * time the resulting observable will wait between the arrival of values from the source before timing out. Note that if
- * `first` is _not_ provided, the value from `each` will be used to check timeout conditions for the arrival of the first
- * value and all subsequent values. If `first` _is_ provided, `each` will only be use to check all values after the first.
- *
- * ### Handling TimeoutErrors
- *
- * If no `with` property was provided, subscriptions to the resulting observable may emit an error of {@link TimeoutError}.
- * The timeout error provides useful information you can examine when you're handling the error. The most common way to handle
- * the error would be with {@link catchError}, although you could use {@link tap} or just the error handler in your `subscribe` call
- * directly, if your error handling is only a side effect (such as notifying the user, or logging).
- *
- * In this case, you would check the error for `instanceof TimeoutError` to validate that the error was indeed from `timeout`, and
- * not from some other source. If it's not from `timeout`, you should probably rethrow it if you're in a `catchError`.
- *
- * ## Examples
- *
- * Emit a {@link TimeoutError} if the first value, and _only_ the first value, does not arrive within 5 seconds
- *
- * ```ts
- * import { interval, timeout } from 'rxjs';
- *
- * // A random interval that lasts between 0 and 10 seconds per tick
- * const source$ = interval(Math.round(Math.random() * 10_000));
- *
- * source$.pipe(
- * timeout({ first: 5_000 })
- * )
- * .subscribe({
- * next: console.log,
- * error: console.error
- * });
- * ```
- *
- * Emit a {@link TimeoutError} if the source waits longer than 5 seconds between any two values or the first value
- * and subscription.
- *
- * ```ts
- * import { timer, timeout, expand } from 'rxjs';
- *
- * const getRandomTime = () => Math.round(Math.random() * 10_000);
- *
- * // An observable that waits a random amount of time between each delivered value
- * const source$ = timer(getRandomTime())
- * .pipe(expand(() => timer(getRandomTime())));
- *
- * source$
- * .pipe(timeout({ each: 5_000 }))
- * .subscribe({
- * next: console.log,
- * error: console.error
- * });
- * ```
- *
- * Emit a {@link TimeoutError} if the source does not emit before 7 seconds, _or_ if the source waits longer than
- * 5 seconds between any two values after the first.
- *
- * ```ts
- * import { timer, timeout, expand } from 'rxjs';
- *
- * const getRandomTime = () => Math.round(Math.random() * 10_000);
- *
- * // An observable that waits a random amount of time between each delivered value
- * const source$ = timer(getRandomTime())
- * .pipe(expand(() => timer(getRandomTime())));
- *
- * source$
- * .pipe(timeout({ first: 7_000, each: 5_000 }))
- * .subscribe({
- * next: console.log,
- * error: console.error
- * });
- * ```
- */
- export function timeout<T, M = unknown>(config: Omit<TimeoutConfig<T, any, M>, 'with'>): OperatorFunction<T, T>;
- /**
- * Returns an observable that will error if the source does not push its first value before the specified time passed as a `Date`.
- * This is functionally the same as `timeout({ first: someDate })`.
- *
- * <span class="informal">Errors if the first value doesn't show up before the given date and time</span>
- *
- * 
- *
- * @param first The date to at which the resulting observable will timeout if the source observable
- * does not emit at least one value.
- * @param scheduler The scheduler to use. Defaults to {@link asyncScheduler}.
- */
- export function timeout<T>(first: Date, scheduler?: SchedulerLike): MonoTypeOperatorFunction<T>;
- /**
- * Returns an observable that will error if the source does not push a value within the specified time in milliseconds.
- * This is functionally the same as `timeout({ each: milliseconds })`.
- *
- * <span class="informal">Errors if it waits too long between any value</span>
- *
- * 
- *
- * @param each The time allowed between each pushed value from the source before the resulting observable
- * will timeout.
- * @param scheduler The scheduler to use. Defaults to {@link asyncScheduler}.
- */
- export function timeout<T>(each: number, scheduler?: SchedulerLike): MonoTypeOperatorFunction<T>;
- /**
- *
- * Errors if Observable does not emit a value in given time span.
- *
- * <span class="informal">Timeouts on Observable that doesn't emit values fast enough.</span>
- *
- * 
- *
- * @see {@link timeoutWith}
- *
- * @return A function that returns an Observable that mirrors behaviour of the
- * source Observable, unless timeout happens when it throws an error.
- */
- export function timeout<T, O extends ObservableInput<any>, M>(
- config: number | Date | TimeoutConfig<T, O, M>,
- schedulerArg?: SchedulerLike
- ): OperatorFunction<T, T | ObservedValueOf<O>> {
- // Intentionally terse code.
- // If the first argument is a valid `Date`, then we use it as the `first` config.
- // Otherwise, if the first argument is a `number`, then we use it as the `each` config.
- // Otherwise, it can be assumed the first argument is the configuration object itself, and
- // we destructure that into what we're going to use, setting important defaults as we do.
- // NOTE: The default for `scheduler` will be the `scheduler` argument if it exists, or
- // it will default to the `asyncScheduler`.
- const {
- first,
- each,
- with: _with = timeoutErrorFactory,
- scheduler = schedulerArg ?? asyncScheduler,
- meta = null!,
- } = (isValidDate(config) ? { first: config } : typeof config === 'number' ? { each: config } : config) as TimeoutConfig<T, O, M>;
- if (first == null && each == null) {
- // Ensure timeout was provided at runtime.
- throw new TypeError('No timeout provided.');
- }
- return operate((source, subscriber) => {
- // This subscription encapsulates our subscription to the
- // source for this operator. We're capturing it separately,
- // because if there is a `with` observable to fail over to,
- // we want to unsubscribe from our original subscription, and
- // hand of the subscription to that one.
- let originalSourceSubscription: Subscription;
- // The subscription for our timeout timer. This changes
- // every time we get a new value.
- let timerSubscription: Subscription;
- // A bit of state we pass to our with and error factories to
- // tell what the last value we saw was.
- let lastValue: T | null = null;
- // A bit of state we pass to the with and error factories to
- // tell how many values we have seen so far.
- let seen = 0;
- const startTimer = (delay: number) => {
- timerSubscription = executeSchedule(
- subscriber,
- scheduler,
- () => {
- try {
- originalSourceSubscription.unsubscribe();
- innerFrom(
- _with!({
- meta,
- lastValue,
- seen,
- })
- ).subscribe(subscriber);
- } catch (err) {
- subscriber.error(err);
- }
- },
- delay
- );
- };
- originalSourceSubscription = source.subscribe(
- createOperatorSubscriber(
- subscriber,
- (value: T) => {
- // clear the timer so we can emit and start another one.
- timerSubscription?.unsubscribe();
- seen++;
- // Emit
- subscriber.next((lastValue = value));
- // null | undefined are both < 0. Thanks, JavaScript.
- each! > 0 && startTimer(each!);
- },
- undefined,
- undefined,
- () => {
- if (!timerSubscription?.closed) {
- timerSubscription?.unsubscribe();
- }
- // Be sure not to hold the last value in memory after unsubscription
- // it could be quite large.
- lastValue = null;
- }
- )
- );
- // Intentionally terse code.
- // If we've `seen` a value, that means the "first" clause was met already, if it existed.
- // it also means that a timer was already started for "each" (in the next handler above).
- // If `first` was provided, and it's a number, then use it.
- // If `first` was provided and it's not a number, it's a Date, and we get the difference between it and "now".
- // If `first` was not provided at all, then our first timer will be the value from `each`.
- !seen && startTimer(first != null ? (typeof first === 'number' ? first : +first - scheduler!.now()) : each!);
- });
- }
- /**
- * The default function to use to emit an error when timeout occurs and a `with` function
- * is not specified.
- * @param info The information about the timeout to pass along to the error
- */
- function timeoutErrorFactory(info: TimeoutInfo<any>): Observable<never> {
- throw new TimeoutError(info);
- }
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