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- import { PartialObserver, ObservableNotification, CompleteNotification, NextNotification, ErrorNotification } from './types';
- import { Observable } from './Observable';
- import { EMPTY } from './observable/empty';
- import { of } from './observable/of';
- import { throwError } from './observable/throwError';
- import { isFunction } from './util/isFunction';
- // TODO: When this enum is removed, replace it with a type alias. See #4556.
- /**
- * @deprecated Use a string literal instead. `NotificationKind` will be replaced with a type alias in v8.
- * It will not be replaced with a const enum as those are not compatible with isolated modules.
- */
- export enum NotificationKind {
- NEXT = 'N',
- ERROR = 'E',
- COMPLETE = 'C',
- }
- /**
- * Represents a push-based event or value that an {@link Observable} can emit.
- * This class is particularly useful for operators that manage notifications,
- * like {@link materialize}, {@link dematerialize}, {@link observeOn}, and
- * others. Besides wrapping the actual delivered value, it also annotates it
- * with metadata of, for instance, what type of push message it is (`next`,
- * `error`, or `complete`).
- *
- * @see {@link materialize}
- * @see {@link dematerialize}
- * @see {@link observeOn}
- * @deprecated It is NOT recommended to create instances of `Notification` directly.
- * Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
- * For example: `{ kind: 'N', value: 1 }`, `{ kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
- * Will be removed in v8.
- */
- export class Notification<T> {
- /**
- * A value signifying that the notification will "next" if observed. In truth,
- * This is really synonymous with just checking `kind === "N"`.
- * @deprecated Will be removed in v8. Instead, just check to see if the value of `kind` is `"N"`.
- */
- readonly hasValue: boolean;
- /**
- * Creates a "Next" notification object.
- * @param kind Always `'N'`
- * @param value The value to notify with if observed.
- * @deprecated Internal implementation detail. Use {@link Notification#createNext createNext} instead.
- */
- constructor(kind: 'N', value?: T);
- /**
- * Creates an "Error" notification object.
- * @param kind Always `'E'`
- * @param value Always `undefined`
- * @param error The error to notify with if observed.
- * @deprecated Internal implementation detail. Use {@link Notification#createError createError} instead.
- */
- constructor(kind: 'E', value: undefined, error: any);
- /**
- * Creates a "completion" notification object.
- * @param kind Always `'C'`
- * @deprecated Internal implementation detail. Use {@link Notification#createComplete createComplete} instead.
- */
- constructor(kind: 'C');
- constructor(public readonly kind: 'N' | 'E' | 'C', public readonly value?: T, public readonly error?: any) {
- this.hasValue = kind === 'N';
- }
- /**
- * Executes the appropriate handler on a passed `observer` given the `kind` of notification.
- * If the handler is missing it will do nothing. Even if the notification is an error, if
- * there is no error handler on the observer, an error will not be thrown, it will noop.
- * @param observer The observer to notify.
- */
- observe(observer: PartialObserver<T>): void {
- return observeNotification(this as ObservableNotification<T>, observer);
- }
- /**
- * Executes a notification on the appropriate handler from a list provided.
- * If a handler is missing for the kind of notification, nothing is called
- * and no error is thrown, it will be a noop.
- * @param next A next handler
- * @param error An error handler
- * @param complete A complete handler
- * @deprecated Replaced with {@link Notification#observe observe}. Will be removed in v8.
- */
- do(next: (value: T) => void, error: (err: any) => void, complete: () => void): void;
- /**
- * Executes a notification on the appropriate handler from a list provided.
- * If a handler is missing for the kind of notification, nothing is called
- * and no error is thrown, it will be a noop.
- * @param next A next handler
- * @param error An error handler
- * @deprecated Replaced with {@link Notification#observe observe}. Will be removed in v8.
- */
- do(next: (value: T) => void, error: (err: any) => void): void;
- /**
- * Executes the next handler if the Notification is of `kind` `"N"`. Otherwise
- * this will not error, and it will be a noop.
- * @param next The next handler
- * @deprecated Replaced with {@link Notification#observe observe}. Will be removed in v8.
- */
- do(next: (value: T) => void): void;
- do(nextHandler: (value: T) => void, errorHandler?: (err: any) => void, completeHandler?: () => void): void {
- const { kind, value, error } = this;
- return kind === 'N' ? nextHandler?.(value!) : kind === 'E' ? errorHandler?.(error) : completeHandler?.();
- }
- /**
- * Executes a notification on the appropriate handler from a list provided.
- * If a handler is missing for the kind of notification, nothing is called
- * and no error is thrown, it will be a noop.
- * @param next A next handler
- * @param error An error handler
- * @param complete A complete handler
- * @deprecated Replaced with {@link Notification#observe observe}. Will be removed in v8.
- */
- accept(next: (value: T) => void, error: (err: any) => void, complete: () => void): void;
- /**
- * Executes a notification on the appropriate handler from a list provided.
- * If a handler is missing for the kind of notification, nothing is called
- * and no error is thrown, it will be a noop.
- * @param next A next handler
- * @param error An error handler
- * @deprecated Replaced with {@link Notification#observe observe}. Will be removed in v8.
- */
- accept(next: (value: T) => void, error: (err: any) => void): void;
- /**
- * Executes the next handler if the Notification is of `kind` `"N"`. Otherwise
- * this will not error, and it will be a noop.
- * @param next The next handler
- * @deprecated Replaced with {@link Notification#observe observe}. Will be removed in v8.
- */
- accept(next: (value: T) => void): void;
- /**
- * Executes the appropriate handler on a passed `observer` given the `kind` of notification.
- * If the handler is missing it will do nothing. Even if the notification is an error, if
- * there is no error handler on the observer, an error will not be thrown, it will noop.
- * @param observer The observer to notify.
- * @deprecated Replaced with {@link Notification#observe observe}. Will be removed in v8.
- */
- accept(observer: PartialObserver<T>): void;
- accept(nextOrObserver: PartialObserver<T> | ((value: T) => void), error?: (err: any) => void, complete?: () => void) {
- return isFunction((nextOrObserver as any)?.next)
- ? this.observe(nextOrObserver as PartialObserver<T>)
- : this.do(nextOrObserver as (value: T) => void, error as any, complete as any);
- }
- /**
- * Returns a simple Observable that just delivers the notification represented
- * by this Notification instance.
- *
- * @deprecated Will be removed in v8. To convert a `Notification` to an {@link Observable},
- * use {@link of} and {@link dematerialize}: `of(notification).pipe(dematerialize())`.
- */
- toObservable(): Observable<T> {
- const { kind, value, error } = this;
- // Select the observable to return by `kind`
- const result =
- kind === 'N'
- ? // Next kind. Return an observable of that value.
- of(value!)
- : //
- kind === 'E'
- ? // Error kind. Return an observable that emits the error.
- throwError(() => error)
- : //
- kind === 'C'
- ? // Completion kind. Kind is "C", return an observable that just completes.
- EMPTY
- : // Unknown kind, return falsy, so we error below.
- 0;
- if (!result) {
- // TODO: consider removing this check. The only way to cause this would be to
- // use the Notification constructor directly in a way that is not type-safe.
- // and direct use of the Notification constructor is deprecated.
- throw new TypeError(`Unexpected notification kind ${kind}`);
- }
- return result;
- }
- private static completeNotification = new Notification('C') as Notification<never> & CompleteNotification;
- /**
- * A shortcut to create a Notification instance of the type `next` from a
- * given value.
- * @param value The `next` value.
- * @return The "next" Notification representing the argument.
- * @deprecated It is NOT recommended to create instances of `Notification` directly.
- * Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
- * For example: `{ kind: 'N', value: 1 }`, `{ kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
- * Will be removed in v8.
- */
- static createNext<T>(value: T) {
- return new Notification('N', value) as Notification<T> & NextNotification<T>;
- }
- /**
- * A shortcut to create a Notification instance of the type `error` from a
- * given error.
- * @param err The `error` error.
- * @return The "error" Notification representing the argument.
- * @deprecated It is NOT recommended to create instances of `Notification` directly.
- * Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
- * For example: `{ kind: 'N', value: 1 }`, `{ kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
- * Will be removed in v8.
- */
- static createError(err?: any) {
- return new Notification('E', undefined, err) as Notification<never> & ErrorNotification;
- }
- /**
- * A shortcut to create a Notification instance of the type `complete`.
- * @return The valueless "complete" Notification.
- * @deprecated It is NOT recommended to create instances of `Notification` directly.
- * Rather, try to create POJOs matching the signature outlined in {@link ObservableNotification}.
- * For example: `{ kind: 'N', value: 1 }`, `{ kind: 'E', error: new Error('bad') }`, or `{ kind: 'C' }`.
- * Will be removed in v8.
- */
- static createComplete(): Notification<never> & CompleteNotification {
- return Notification.completeNotification;
- }
- }
- /**
- * Executes the appropriate handler on a passed `observer` given the `kind` of notification.
- * If the handler is missing it will do nothing. Even if the notification is an error, if
- * there is no error handler on the observer, an error will not be thrown, it will noop.
- * @param notification The notification object to observe.
- * @param observer The observer to notify.
- */
- export function observeNotification<T>(notification: ObservableNotification<T>, observer: PartialObserver<T>) {
- const { kind, value, error } = notification as any;
- if (typeof kind !== 'string') {
- throw new TypeError('Invalid notification, missing "kind"');
- }
- kind === 'N' ? observer.next?.(value!) : kind === 'E' ? observer.error?.(error) : observer.complete?.();
- }
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