Question

Consider the following CoffeeScript class:

class Event
    trigger : (args...) =>
        ...

    bind : (args...) =>
        ...

The use case would be:

message_received = new Event()
message_received.bind(alert)                                       
message_received.trigger('Hello world!') # calls alert('Hello world') 

Is there a way to write the Event class in such manner that the .trigger(...) call would have the “callable object” shortcut:

message_received('Hello world')  # ?

Thank you!

Answer 1

You need to return a function from the constructor, which is extended with the properties from the current instance (which in turn is inherit from Event.prototype).

class Event
    constructor : ->
        shortcut = -> shortcut.trigger(arguments...)
        for key, value of @
            shortcut[key] = value
        return shortcut

    trigger : (args...) =>
        ...

    bind : (args...) =>
        ...

Compiled result