How to use RxJS 5 buffer function?

Question

I googled a lot, tried to look at d.ts file but still cannot understand what is wrong. Cannot find example of RxJs5 how to use this function.

var source = Observable.fromEvent(document.body, 'keypress');

    var delayedSource = source.delay(1000);

    var obs = source



      .buffer(() => {
        return   delayedSource;
      })

      .map((clickBuffer) => {
        return clickBuffer.length;
      });

I am getting error:

Error:(166, 15) TS2345: Argument of type '() => Observable<{}>' is not assignable to parameter of type 'Observable'. Property '_isScalar' is missing in type '() => Observable<{}>'.

buffer.d.ts looks this, I guess I should understand from this, but I can't.

import { Observable } from '../Observable';
/**
 * Buffers the incoming observable values until the passed `closingNotifier`
 * emits a value, at which point it emits the buffer on the returned observable
 * and starts a new buffer internally, awaiting the next time `closingNotifier`
 * emits.
 *
 * <img src="./img/buffer.png" width="100%">
 *
 * @param {Observable<any>} closingNotifier an Observable that signals the
 * buffer to be emitted} from the returned observable.
 * @returns {Observable<T[]>} an Observable of buffers, which are arrays of
 * values.
 */
export declare function buffer<T>(closingNotifier: Observable<any>): Observable<T[]>;
export interface BufferSignature<T> {
    (closingNotifier: Observable<any>): Observable<T[]>;
}

This question came from this: Counting keypresses per second with angular 2 Rxjs

you're passing a function in but you should be passing the observable. — Benjamin Gruenbaum, Apr 03 '16 at 08:00

score 0 · Answer 1 · answered Apr 03 '16 at 08:22

Based on Benjamin Gruenbaum comment, this solves the problem:

var source = Observable.fromEvent(document.body, 'keypress');

var delayedSource = source.delay(1000);

var obs = source

      .buffer(delayedSource)

      .map((clickBuffer) => {
        return clickBuffer.length;
      })

How to use RxJS 5 buffer function?

1 Answers1