Observer pattern Straightforward implementation

observer-simple.js

// Observer pattern
// Straightforward implementation

class Notification {
  constructor() {
    this.subs = []; 
  }

  subscribeMe = (subscriptor) => {
    this.subs.push(subscriptor);
    console.log("New subscriber ",subscriptor);
  }

  notify = (newMessage) => {
     console.log("An event occured!");
     for (let i = 0; i < this.subs.length; ++i) {
       this.subs[i](newMessage);
     }
  }
}

// We can define multiple functions
// that will be subscribed to the 
// notification mechanism
const sayAlert = (msj) => {
  alert(msj);
}

const logger = (msj) => {
  console.log(msj);
}

// Then glue it all!
const notifier = new Notification();
notifier.subscribeMe(sayAlert);
notifier.subscribeMe(logger);

// And send a notification to all the
// subscribers
notifier.notify('You had a new message');