new ValueStream()
Provides a stream of topic events, specific to the topic selector that this ValueStream was created for, with topic values provided as instances of the associated DataType.
ValueStream inherits all functions defined on Stream.
Properties:
Name | Type | Description |
---|---|---|
selector |
String | The selector this subscription was created for |
Fires:
- ValueStream#event:open
- ValueStream#event:close
- ValueStream#event:value
- ValueStream#event:subscribe
- ValueStream#event:unsubscribe
- ValueStream#event:error
Examples
// Create a value stream for topic 'foo' session.stream('foo').asType(datatype).on('value', function(topic, specification, newValue, oldValue) { // Receive updates for the topic 'foo' }); // Then subscribe to topic 'foo' session.subscribe('foo');
// Attach multiple listeners for events session.stream('foo').asType(datatype).on({ subscribe : function(topic, specification) { // Subscribed to a particular topic }, unsubscribe : function(topic, specification, reason) { // Unsubscribed from a particular topic }, value : function(topic, specification, newValue, oldValue) { // Value from a topic } });
Extends
Methods
-
close()
-
Close the subscription. No further events will be emitted.
- Overrides:
-
off(event [, listener])
-
Remove a listener from a specified event.
Parameters:
Name Type Argument Description event
String The event to remove listeners from
listener
function <optional>
The listener to remove. All listeners for the event are removed if this is not specified
- Inherited From:
Returns:
This stream.
- Type
- Stream
Examples
// Bind a single listener to the 'foo' event and then deregister it var listener = function() {}; stream.on('foo', listener); stream.off('foo', listener);
// Bind a listener to the 'foo' event and deregister all listeners var listener = function() {}; stream.on('foo', listener); stream.off('foo');
-
on(events [, listener])
-
Register listeners against events.
A single listener may be bound to an event by passing the event name and listener function.
Multiple listeners may be bound by passing in an object, mapping event names to listener functions.
Parameters:
Name Type Argument Description events
String | Object The event name or object mapping event names to listeners
listener
function <optional>
The listener to bind to the event, if passed as string.
- Inherited From:
Returns:
This stream.
- Type
- Stream
Examples
// Bind a single listener to the 'foo' event stream.on('foo', function(arg1, arg2) { console.log("Called for 'foo' event", arg1, arg2); });
// Bind multiple listeners stream.on({ foo : function() { ... }, bar : function() { ... }, baz : function() { ... } });