a tiny functional event emitter / pubsub.

pubsub.s1

// a tiny functional event emitter / pubsub.

fn Emitter(){
    all := {'*':{}}
    return {
        // A Dynamic object/Map of event names to registered handler functions.
        'all':all,
        // Register an event handler for the given type.
        'on':fn(type, handler){
            (all[type])?push(all[type], handler):set(all, type, handler)
        },
        // Invoke all handlers for the given type.
        'emit': fn(type, evt) {
            all[type]?map(all[type], fn(handler){ handler(evt) }):{}
            // map(all.get('*').slice(), fn(handler){handler(evt)})
        }
    }
}

fn set(m, k, v){
    m[k] = v
    return m
}

/*
class Emitter {
    all
    
    fn __init() {
        $all = {}
    }
    fn all() {
        return $all
    }
    fn on(type, handler) {
        handlers := $all[type]
        if(handlers!=null) {
            push($all[type], handler)
        } else {
            $all[type] = handler
        }
    }
    fn emit(type, evt){
        handlers := $all[type]
        if(handlers) {
            map($all[type], fn(handler){ handler(evt) })
        }
    }
}
*/

emitter := Emitter()

// listen to an event
emitter.on('foo', fn(e){log('foo', e)})

// fire an event
emitter.emit('foo', {'a': 'b'})

// working with handler references:
fn onFoo(e) { log('foo', e) }
emitter.on('foo', onFoo)   // listen

// fire an event
emitter.emit('foo', {'a': 'c'})