import { PartialObserver } from './types';
|
import { Observable } from './Observable';
|
import { empty } from './observable/empty';
|
import { of } from './observable/of';
|
import { throwError } from './observable/throwError';
|
import { deprecate } from 'util';
|
|
// TODO: When this enum is removed, replace it with a type alias. See #4556.
|
/**
|
* @deprecated NotificationKind is deprecated as const enums are not compatible with isolated modules. Use a string literal instead.
|
*/
|
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}
|
*
|
* @class Notification<T>
|
*/
|
export class Notification<T> {
|
hasValue: boolean;
|
|
constructor(public kind: 'N' | 'E' | 'C', public value?: T, public error?: any) {
|
this.hasValue = kind === 'N';
|
}
|
|
/**
|
* Delivers to the given `observer` the value wrapped by this Notification.
|
* @param {Observer} observer
|
* @return
|
*/
|
observe(observer: PartialObserver<T>): any {
|
switch (this.kind) {
|
case 'N':
|
return observer.next && observer.next(this.value);
|
case 'E':
|
return observer.error && observer.error(this.error);
|
case 'C':
|
return observer.complete && observer.complete();
|
}
|
}
|
|
/**
|
* Given some {@link Observer} callbacks, deliver the value represented by the
|
* current Notification to the correctly corresponding callback.
|
* @param {function(value: T): void} next An Observer `next` callback.
|
* @param {function(err: any): void} [error] An Observer `error` callback.
|
* @param {function(): void} [complete] An Observer `complete` callback.
|
* @return {any}
|
*/
|
do(next: (value: T) => void, error?: (err: any) => void, complete?: () => void): any {
|
const kind = this.kind;
|
switch (kind) {
|
case 'N':
|
return next && next(this.value);
|
case 'E':
|
return error && error(this.error);
|
case 'C':
|
return complete && complete();
|
}
|
}
|
|
/**
|
* Takes an Observer or its individual callback functions, and calls `observe`
|
* or `do` methods accordingly.
|
* @param {Observer|function(value: T): void} nextOrObserver An Observer or
|
* the `next` callback.
|
* @param {function(err: any): void} [error] An Observer `error` callback.
|
* @param {function(): void} [complete] An Observer `complete` callback.
|
* @return {any}
|
*/
|
accept(nextOrObserver: PartialObserver<T> | ((value: T) => void), error?: (err: any) => void, complete?: () => void) {
|
if (nextOrObserver && typeof (<PartialObserver<T>>nextOrObserver).next === 'function') {
|
return this.observe(<PartialObserver<T>>nextOrObserver);
|
} else {
|
return this.do(<(value: T) => void>nextOrObserver, error, complete);
|
}
|
}
|
|
/**
|
* Returns a simple Observable that just delivers the notification represented
|
* by this Notification instance.
|
* @return {any}
|
*/
|
toObservable(): Observable<T> {
|
const kind = this.kind;
|
switch (kind) {
|
case 'N':
|
return of(this.value);
|
case 'E':
|
return throwError(this.error);
|
case 'C':
|
return empty();
|
}
|
throw new Error('unexpected notification kind value');
|
}
|
|
private static completeNotification: Notification<any> = new Notification('C');
|
private static undefinedValueNotification: Notification<any> = new Notification('N', undefined);
|
|
/**
|
* A shortcut to create a Notification instance of the type `next` from a
|
* given value.
|
* @param {T} value The `next` value.
|
* @return {Notification<T>} The "next" Notification representing the
|
* argument.
|
* @nocollapse
|
*/
|
static createNext<T>(value: T): Notification<T> {
|
if (typeof value !== 'undefined') {
|
return new Notification('N', value);
|
}
|
return Notification.undefinedValueNotification;
|
}
|
|
/**
|
* A shortcut to create a Notification instance of the type `error` from a
|
* given error.
|
* @param {any} [err] The `error` error.
|
* @return {Notification<T>} The "error" Notification representing the
|
* argument.
|
* @nocollapse
|
*/
|
static createError<T>(err?: any): Notification<T> {
|
return new Notification('E', undefined, err);
|
}
|
|
/**
|
* A shortcut to create a Notification instance of the type `complete`.
|
* @return {Notification<any>} The valueless "complete" Notification.
|
* @nocollapse
|
*/
|
static createComplete(): Notification<any> {
|
return Notification.completeNotification;
|
}
|
}
|
