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Diffstat (limited to 'node_modules/rxjs/src/internal/Notification.ts')
| -rw-r--r-- | node_modules/rxjs/src/internal/Notification.ts | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/node_modules/rxjs/src/internal/Notification.ts b/node_modules/rxjs/src/internal/Notification.ts new file mode 100644 index 0000000..cf344c4 --- /dev/null +++ b/node_modules/rxjs/src/internal/Notification.ts @@ -0,0 +1,238 @@ +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?.(); +} |