CODEWITHSUNDEEP
javascriptbufferrxjs
jney
jney

Reputation: 1912

buffering with time and custom event

I started using rxjs yesterday. i would like to achieve the following behavior:

I want my buffer to be produced with both time and custom events. Imagine, every 2000 ms my buffer is produced (like standard bufferWithTime function behavior) and for some special event, a buffer is produced and the timer, is re initialized.

Here is a basic representation :

Content of buffer A: [1, 2], B: [3, 4, 5], C: [6, 7], D: [8, 9].

Time segments A, B, D have the same duration, 2000 ms.

Time segment C was shorter because special event 7 was triggered and buffer was produced.

How can i do this ?

Upvotes: 0

Views: 352

Answers (1)

user3743222
user3743222

Reputation: 18665

Can you try this (jsfiddle)? 

// Helper functions
function randomDelay(bottom, top) {
  return Math.floor( Math.random() * ( 1 + top - bottom ) ) + bottom;
}

// Simulation of random sequence
var source$ = Rx.Observable
  .range(1, 30)
  .concatMap(function (x) {
    return Rx.Observable.of(x).delay(randomDelay(10,500));
  });

var intervalBetween = 1000; // should be 2000ms in your case
var dummyStart$ = Rx.Observable.return({});
var specialEvent$ = Rx.Observable.fromEvent(document, 'click');
var opening$ = dummyStart$.concat(specialEvent$).flatMapLatest(function(x){return Rx.Observable.timer(0, intervalBetween)});
var buffers$ = source$.buffer(opening$).skip(1);

source$.subscribe(function(x){console.log('source', x)})

buffers$.subscribe(function(buffer){
   console.log('buffer', buffer);
});

The idea here is to use the buffer operator with the signature Rx.Observable.prototype.window(windowBoundaries);. That should give you non-overlapping buffers which emit synchronized with the windowBoundaries signal.

There is a small trick (dummyStart) to kickoff the timer immediately with a false specialEvent. That produce an empty buffer as first value, which is removed by skip(1).

Upvotes: 1

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