Rx.BehaviorSubject
class
Represents a value that changes over time. Observers can subscribe to the subject to receive the last (or initial) value and all subsequent notifications.
This class inherits both from the Rx.Observable
and Rx.Observer
classes.
Usage
The follow example shows the basic usage of an Rx.BehaviorSubject
class.
/* Initialize with initial value of 42 */
var subject = new Rx.BehaviorSubject(42);
var subscription = subject.subscribe(
function (x) {
console.log('Next: ' + x.toString());
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: 42
subject.onNext(56);
// => Next: 56
subject.onCompleted();
// => Completed
Location
- rx.binding.js
BehaviorSubject Constructor
BehaviorSubject Instance Methods
Inherited Classes
BehaviorSubject Constructor
Rx.BehaviorSubject(initialValue)
Initializes a new instance of the Rx.BehaviorSubject
class which creates a subject that caches its last value and starts with the specified value.
参数
initialValue
(Any): Initial value sent to observers when no other value has been received by the subject yet.
例
var subject = new Rx.BehaviorSubject(56);
subject.onCompleted();
var subscription = source.subscribe(
function (x) {
console.log('Next: ' + x);
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: 56
subject.onNext(42);
// => Next: 42
subject.onCompleted();
// => Completed
Location
= rx.binding.js
BehaviorSubject Instance Methods
Rx.BehaviorSubject.prototype.dispose()
Unsubscribe all observers and release resources.
例
var subject = new Rx.BehaviorSubject();
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.BehaviorSubject.prototype.hasObservers()
Indicates whether the subject has observers subscribed to it.
返回值
(Boolean): Returns true
if the Subject has observers, else false
.
例
var subject = new Rx.BehaviorSubject();
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