Subject

class stable

A Subject is a special type of Observable that allows values to be multicasted to many Observers. Subjects are like EventEmitters.

class Subject<T> extends Observable implements SubscriptionLike { static create: Function constructor() observers: Observer<T>[] closed: false isStopped: false hasError: false thrownError: any lift<R>(operator: Operator<T, R>): Observable<R> next(value?: T) error(err: any) complete() unsubscribe() _trySubscribe(subscriber: Subscriber<T>): TeardownLogic _subscribe(subscriber: Subscriber<T>): Subscription asObservable(): Observable<T> // inherited from index/Observable static create: Function static if: typeof iif static throw: typeof throwError constructor(subscribe?: (this: Observable<T>, subscriber: Subscriber<T>) => TeardownLogic) _isScalar: boolean source: Observable<any> operator: Operator<any, T> lift<R>(operator: Operator<T, R>): Observable<R> subscribe(observerOrNext?: PartialObserver<T> | ((value: T) => void), error?: (error: any) => void, complete?: () => void): Subscription _trySubscribe(sink: Subscriber<T>): TeardownLogic forEach(next: (value: T) => void, promiseCtor?: PromiseConstructorLike): Promise<void> pipe(...operations: OperatorFunction<any, any>[]): Observable<any> toPromise(promiseCtor?: PromiseConstructorLike): Promise<T> }

Subclasses

BehaviorSubject
ReplaySubject
AsyncSubject

Description

Every Subject is an Observable and an Observer. You can subscribe to a Subject, and you can call next to feed values as well as error and complete.

Static Properties

Property	Type	Description
create	`Function`

Constructor

constructor()

Parameters

There are no parameters.

Properties

Property	Type	Description
observers	`Observer<T>[]`
closed	`false`
isStopped	`false`
hasError	`false`
thrownError	`any`

Methods

lift()

lift<R>(operator: Operator<T, R>): Observable<R>

Parameters

operator

Type: Operator.

Returns

Observable<R>

next()

next(value?: T)

Parameters

value

Optional. Default is undefined.

Type: T.

error()

error(err: any)

Parameters

err	Type: `any`.

complete()
complete() Parameters There are no parameters.

complete()

Parameters

There are no parameters.

unsubscribe()
unsubscribe() Parameters There are no parameters.

unsubscribe()

Parameters

There are no parameters.

_trySubscribe()

_trySubscribe(subscriber: Subscriber<T>): TeardownLogic

Parameters

subscriber

Type: Subscriber.

Returns

TeardownLogic

_subscribe()

_subscribe(subscriber: Subscriber<T>): Subscription

Parameters

subscriber

Type: Subscriber.

Returns

Subscription

asObservable()
Creates a new Observable with this Subject as the source. You can do this to create customize Observer-side logic of the Subject and conceal it from code that uses the Observable.
asObservable(): Observable<T> Parameters There are no parameters. Returns `Observable<T>`: Observable that the Subject casts to

asObservable()

Creates a new Observable with this Subject as the source. You can do this to create customize Observer-side logic of the Subject and conceal it from code that uses the Observable.

asObservable(): Observable<T>

Parameters

There are no parameters.

Returns

Observable<T>: Observable that the Subject casts to