mapStream_.ts

namespace mapStream_ {


    export interface EventGenerator {
        onEvent: (h: EventHandler) => void
    }

    type Food = string
    export type Event = Food
    export type EventHandler = (f: Event) => void
    const foodStream : EventGenerator = 
        {
            onEvent: (handler: EventHandler) => {
                setTimeout( () => handler("galinha") , 1000 )
                setTimeout( () => handler("vaca") , 2000 )
                setTimeout( () => handler("milho"), 3000 )
            }
        }
    

    foodStream.onEvent( (food: Event):void => console.log(food) )

}