Rx.Observable.prototype.window()
The window
method periodically subdivide items from an Observable into Observable windows and emit these windows rather than emitting the items one at a time.
Window is similar to buffer
, but rather than emitting packets of items from the original Observable
, it emits Observables, each one of which emits a subset of items from the original Observable
and then terminates with an onCompleted
call.
Like buffer
, window
has many varieties, each with its own way of subdividing the original Observable
into the resulting Observable
emissions, each one of which contains a "window" onto the original emitted items. In the terminology of the window
method, when a window "opens," this means that a new Observable
is emitted and that Observable
will begin emitting items emitted by the source Observable
. When a window "closes," this means that the emitted Observable stops emitting items from the source Observable and calls its Subscribers' onCompleted
method and terminates.
With window closing selector
Rx.Observable.prototype.window(windowClosingSelector);
This version of window
opens its first window immediately. It closes the currently open window and immediately opens a new one each time it observes an object emitted by the Observable
that is returned from windowClosingSelector
. In this way, this version of window
emits a series of non-overlapping windows whose collective onNext
emissions correspond one-to-one with those of the source Observable.
Arguments
windowClosingSelector
(Function
): A function invoked to define the closing of each produced window.
Returns
(Observable
): An observable sequence of windows.
Example
// With closings
var source = Rx.Observable.timer(0, 50)
.window(function () { return Rx.Observable.timer(125); })
.take(3)
.flatMap(function (x) { return x.toArray(); });
var subscription = source.subscribe(
function (x) {
console.log('Next: %s', x);
},
function (err) {
console.log('Error: %s', err);
},
function () {
console.log('Completed');
});
// => Next: 0,1,2
// => Next: 3,4,5
// => Next: 6,7
// => Completed
With window opening and window closing selector
Rx.Observable.prototype.window(windowOpenings, windowClosingSelector);
This version of window
opens a window whenever it observes the windowOpenings
Observable
emit an Opening object and at the same time calls windowClosingSelector
to generate a closing Observable
associated with that window. When that closing Observable
emits an object, window
closes that window. Since the closing of currently open windows and the opening of new windows are activities that are regulated by independent Observables, this version of window
may create windows that overlap (duplicating items from the source Observable
) or that leave gaps (discarding items from the source Observable).
Arguments
windowOpenings
(Observable
): Observable sequence whose elements denote the creation of new windowswindowClosingSelector
(Function
): A function invoked to define the closing of each produced window.
Returns
(Observable
): An observable sequence of windows.
Example
/* Using Openings and Closing Selector */
var openings = Rx.Observable.interval(200);
var source = Rx.Observable.interval(50)
.window(openings, function (x) { return Rx.Observable.timer(x + 100); })
.take(3);
var subscription = source.subscribe(
function (x) {
console.log('Next: %s', x);
},
function (err) {
console.log('Error: %s', err);
},
function () {
console.log('Completed');
});
// => Next: 3,4
// => Next: 7,8
// => Next: 11,12
// => Completed
With boundaries
Rx.Observable.prototype.window(windowBoundaries);
This version of window
returns an Observable
that emits non-overlapping buffered items from the source Observable
each time the specified boundary Observable emits an item.
Arguments
windowBoundaries
(Observable
): Sequence of window boundary markers. The current window is closed and a new window is opened upon receiving a boundary marker.
Returns
(Observable
): An observable sequence of windows.
Example
/* With window boundaries */
var openings = Rx.Observable.interval(500);
// Convert the window to an array
var source = Rx.Observable.timer(0, 100)
.window(openings)
.take(3)
.flatMap(function (x) { return x.toArray(); });
var subscription = source.subscribe(
function (x) {
console.log('Next: %s', x);
},
function (err) {
console.log('Error: %s', err);
},
function () {
console.log('Completed');
});
// => Next: 0,1,2,3,4
// => Next: 5,6,7,8,9,10
// => Next: 11,12,13,14,15
// => Completed
Location
File:
Dist:
Prerequisites:
NPM Packages:
NuGet Packages:
Unit Tests: