Returns a connectable observable sequence that shares a single subscription to the underlying sequence containing only the last notification.

publishLast<T>(): UnaryFunction<Observable<T>, ConnectableObservable<T>>

Parameters

There are no parameters.

Returns

UnaryFunction<Observable<T>, ConnectableObservable<T>>: An observable sequence that contains the elements of a sequence produced by multicasting the source sequence.

Description

Similar to publish, but it waits until the source observable completes and stores the last emitted value. Similarly to publishReplay and publishBehavior, this keeps storing the last value even if it has no more subscribers. If subsequent subscriptions happen, they will immediately get that last stored value and complete.

Example

import { interval } from 'rxjs';
import { publishLast, tap, take } from 'rxjs/operators';

const connectable =
  interval(1000)
    .pipe(
      tap(x => console.log("side effect", x)),
      take(3),
      publishLast());

connectable.subscribe(
  x => console.log(  "Sub. A", x),
  err => console.log("Sub. A Error", err),
  () => console.log( "Sub. A Complete"));

connectable.subscribe(
  x => console.log(  "Sub. B", x),
  err => console.log("Sub. B Error", err),
  () => console.log( "Sub. B Complete"));

connectable.connect();

// Results:
//    "side effect 0"
//    "side effect 1"
//    "side effect 2"
//    "Sub. A 2"
//    "Sub. B 2"
//    "Sub. A Complete"
//    "Sub. B Complete"

See Also

• ConnectableObservable
• publish
• publishReplay
• publishBehavior