js.event_emitter

 
import EventEmitter from "js.event_emitter";
 
class Cat extends EventEmitter {}
 
class Dog extends EventEmitter {
 
    constructor(){ 
        this.name = "Bob";
    }
 
    gav(){ 
        console.log( this.name + " gav" ); 
    }
 
    manyGav(){ 
        console.log( this.name + " gav gav gav" ); 
    }
 
}
 
 
let dog = new Dog,
    cat = new Cat;
  
cat.on(                              // attach event handler, call on every trigger
    "run",                           // event name
    dog.gav,                         // event handler
    dog                              // callback context
);
 
cat.one( "run", dog.manyGav, dog );  // call on first trigger
 
cat.trigger( "run" );                // > "Bob gav"
                                     // > "Bob gav gav gav"
cat.trigger( "run" );                // > "Bob gav"
cat.trigger( "run" );                // > "Bob gav"
 
cat.off();                           // detach all handlers of all events
cat.off( "run" );                    // detach all handlers of "run" event
cat.off( "run", dog.gav );           // detach dog.gav handler of "run" event
cat.off( "run", dog.gav, dog );      // detach dog.gav handler of "run" event when context is dog