Observer pattern in JavaScript

index.js

/**
 * Subject or Observable
 */
function Observable() {
  this.observers = [];
}

/**
 * Add observer to observable
 * @param {object} observer
 */
Observable.prototype.subcribe = function (observer) {
  this.observers.push(observer);
};

/**
 * Remove observer from observable
 * @param {object} observer
 */
Observable.prototype.unsubcribe = function (observer) {
  this.observers = this.observers.filter(function (obs) {
    return obs !== observer;
  });
};

/**
 * Notify observers
 * @param {any} data
 */
Observable.prototype.notify = function (data) {
  this.observers.forEach(function (observer) {
    observer.update(data);
  });
};

/**
 * Listener or Observer
 */
function Observer() {
  this.update = function (data) {};
}

// ------------------------------------------------------------

const observer1 = new Observer();
observer1.update = function (data) {
  console.log('observer1: ' + data);
};

const observer2 = new Observer();
observer2.update = function (data) {
  console.log('observer2: ' + data);
};

const observer3 = new Observer();
observer3.update = function (data) {
  console.log('observer3: ' + data);
};

const observable = new Observable();

observable.subcribe(observer1);
observable.subcribe(observer2);
observable.subcribe(observer3);

observable.notify('hello');

observable.unsubcribe(observer2);

observable.notify('hello');

observer.svg