replaysubject.md

Rx.ReplaySubject class

Represents an object that is both an observable sequence as well as an observer. Each notification is broadcasted to all subscribed and future observers, subject to buffer trimming policies.

This class inherits both from the Rx.Observable and Rx.Observer classes.

Usage

The follow example shows the basic usage of an Rx.ReplaySubject class. Note that this only holds the past two items in the cache.

var subject = new Rx.ReplaySubject(2 /* buffer size */);

subject.onNext('a');
subject.onNext('b');
subject.onNext('c');

var subscription = subject.subscribe(
    function (x) {
        console.log('Next: ' + x.toString());
    },
    function (err) {
        console.log('Error: ' + err);   
    },
    function () {
        console.log('Completed');   
    });

// => Next: b
// => Next: c

subject.onNext('d');
// => Next: d

Location

• rx.binding.js

ReplaySubject Constructor

• constructor

ReplaySubject Instance Methods

• dispose
• hasObservers

Inherited Classes

• Rx.Observable
• Rx.Observer

ReplaySubject Constructor

Rx.ReplaySubject([bufferSize], [windowSize], [scheduler])

# Ⓢ

Initializes a new instance of the Rx.ReplaySubject class with the specified buffer size, window and scheduler.

Arguments

1. [bufferSize = Number.MAX_VALUE] (Number): Maximum element count of the replay buffer.
2. [windowSize = NUMBER.MAX_VALUE] (Number): Maximum time length of the replay buffer.
3. [scheduler = Rx.Scheduler.currentThread] (Scheduler): Scheduler the observers are invoked on.

Example

var subject = new Rx.ReplaySubject(
    2 /* buffer size */, 
    null /* unlimited time buffer */,
    Rx.Scheduler.timeout);

subject.onNext('a');
subject.onNext('b');
subject.onNext('c');

var subscription = subject.subscribe(
    function (x) {
        console.log('Next: ' + x.toString());
    },
    function (err) {
        console.log('Error: ' + err);   
    },
    function () {
        console.log('Completed');   
    });

// => Next: b
// => Next: c

subject.onNext('d');
// => Next: d

Location

• rx.binding.js

---

ReplaySubject Instance Methods

Rx.ReplaySubject.prototype.dispose()

# Ⓢ

Unsubscribe all observers and release resources.

Example

var subject = new Rx.ReplaySubject();
    
var subscription = subject.subscribe(
    function (x) {
        console.log('Next: ' + x.toString());
    },
    function (err) {
        console.log('Error: ' + err);   
    },
    function () {
        console.log('Completed');   
    });

subject.onNext(42);
// => Next: 42

subject.onCompleted();
// => Completed

subject.dispose();

try {
	subject.onNext(56);
} catch (e) {
	console.log(e.message);
}

// => Object has been disposed 

Location

• rx.binding.js

---

Rx.ReplaySubject.prototype.hasObservers()

# Ⓢ

Indicates whether the subject has observers subscribed to it.

Returns

(Boolean): Returns true if the Subject has observers, else false.

Example

var subject = new Rx.ReplaySubject();

console.log(subject.hasObservers());

// => false
    
var subscription = subject.subscribe(
    function (x) {
        console.log('Next: ' + x.toString());
    },
    function (err) {
        console.log('Error: ' + err);   
    },
    function () {
        console.log('Completed');   
    });

console.log(subject.hasObservers());

// => true

Location

• rx.binding.js

---