reactive-programming-exmaple.js

class Observer {
  constructor() {
    // store of subscribers
    this.observers = [];
  }
  subscribe(aFunction) {
    this.observers.push(aFunction);
  }

  broadcast(data) {
    this.observers.forEach(func => {
      func(data);
      console.log("\n");
    });
  }
}
let posts = [];
const Ob = new Observer();

const subscriberOne = data => {
  console.log("From function One, Data:", data);
  posts.push(data);
};

const subscriberTwo = data => {
  console.log("From function Two, Data: ", data);
  console.log(posts);
};

Ob.subscribe(subscriberOne);
Ob.subscribe(subscriberTwo);

setInterval(() => {
  Ob.broadcast(Math.random());
}, 500);

class Iterator {
  constructor() {
    this.currentIndex = 0;
    this.listPosts = ["Somsri", "Somchai", "Sommai", "Manee", "Manah"];
  }

  first() {
    this.reset();
    return this.listPosts[this.currentIndex];
  }

  next() {
    return this.listPosts[this.currentIndex++];
  }

  reset() {
    this.currentIndex = 0;
  }
}

const Iter = new Iterator();
console.log(Iter.first());
console.log(Iter.next());
console.log(Iter.next());