> [Wiki](Home) ▸ [[API Reference|API-Reference]] ▸ **Signal**
# Signal
> events-like
Signal is a function with listeners which can be emitted.
Access it with:
```javascript
const { signal } = Neft;
```
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee)
## Table of contents
* [Signal](#signal)
* [STOP_PROPAGATION](#stoppropagation)
* [create](#create)
* [isEmpty](#isempty)
* [**Class** Signal](#class-signal)
* [emit](#emit)
* [connect](#connect)
* [disconnect](#disconnect)
* [disconnectAll](#disconnectall)
* [Glossary](#glossary)
#STOP_PROPAGATION
- Syntax
*Integer* STOP_PROPAGATION- Type
- Integer
Special constant used to stop calling further listeners.
Must be returned by the listener function.
```javascript
var obj = {};
signal.create(obj, 'onPress');
obj.onPress(function(){
console.log('listener 1');
return signal.STOP_PROPAGATION;
});
// this listener won't be called, because first listener will capture this signal
obj.onPress(function(){
console.log('listener 2');
});
obj.onPress.emit();
// listener 1
```
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee#integer-stoppropagation)
#create
- Syntax
*Signal* create([*NotPrimitive* object, *String* name])- Parameters
- Type
- Signal
Creates a new signal in the given object under the given name property.
Returns created signal.
```javascript
var obj = {};
signal.create(obj, 'onRename');
obj.onRename.connect(function(){
console.log(arguments);
});
obj.onRename.emit('Max', 'George');
// {0: "Max", 1: "George"}
```
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee#signal-createnotprimitive-object-string-name)
#isEmpty
- Syntax
*Boolean* isEmpty(*Signal* signal)- Parameters
- Returns
- Boolean
Returns `true` if the given signal has no listeners.
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee#boolean-isemptysignal-signal)
# **Class** Signal
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee)
##emit
- Syntax
Signal::emit([*Any* argument1, *Any* argument2])- Prototype method of
- Signal
- Parameters
- argument1 — Any — optional
- argument2 — Any — optional
Call all of the signal listeners with the given arguments (2 maximally).
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee#signalemitany-argument1-any-argument2)
##connect
- Syntax
Signal::connect(*Function* listener, [*Any* context])- Prototype method of
- Signal
- Parameters
- listener — Function
- context — Any — optional
Adds the given listener function into the signal listeners.
By default, the signal function works like this method.
```javascript
var obj = {};
signal.create(obj, 'onPress');
obj.onPress(function(){
console.log('listener 1');
});
obj.onPress.connect(function(){
console.log('listener 2');
});
obj.onPress.emit()
// listener 1
// listener 2
```
The given context will be used as a context in listener calling.
By default, the listener is called with the object on which the signal is created.
```javascript
var obj = {standard: true};
signal.create(obj, 'onPress');
var fakeContext = {fake: true};
obj.onPress(function(){
console.log(this);
}, fakeContext);
obj.onPress(function(){
console.log(this);
});
obj.onPress.emit();
// {fake: true}
// {standard: true}
```
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee#signalconnectfunction-listener-any-context)
##disconnect
- Syntax
Signal::disconnect(*Function* listener, [*Any* context])- Prototype method of
- Signal
- Parameters
- listener — Function
- context — Any — optional
Returns the given listener function from the signal listeners.
```javascript
var obj = {};
signal.create(obj, 'onPress');
var listener = function(){
console.log('listener called!');
};
obj.onPress.connect(listener);
obj.onPress.disconnect(listener);
obj.onPress.emit()
// no loggs...
```
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee#signaldisconnectfunction-listener-any-context)
##disconnectAll
- Syntax
Signal::disconnectAll()- Prototype method of
- Signal
Removes all the signal listeners.
> [`Source`](/Neft-io/neft/blob/00d48f19a9b22932ace5d660101e9fa2b6991fb9/src/signal/index.litcoffee#signaldisconnectall)
# Glossary
- [Signal](#class-signal)