Just a poc of the mediator pattern

mediator.js

// with class pattern
class Client {
  constructor(name) {
    this.name = name;
    this.mediator = null;
  }

  send(message, to) {
    if (!this.mediator) {
      throw ('you need to register to a mediator first')
    }
    this.mediator.send(message, this, to);
  }
  receive(message, from) {
    console.log(from.name + " to " + this.name + ": " + message);
  }
}

class Mediator {
  constructor() {
    this.clients = {};
  }

  register(client) {
    this.clients[client.name] = client;
    client.mediator = this;
  }

  send(message, from, to) {
    if (to) {
      to.receive(message, from);
    } else {
      for (const key in this.clients) {
        if (this.clients[key] !== from) {
          this.clients[key].receive(message, from);
        }
      }
    }
  }
}


var user1 = new Client("user1");
var user2 = new Client("user2");
var user3 = new Client("user3");
var user4 = new Client("user4");

var mediator = new Mediator();
mediator.register(user1);
mediator.register(user2);
mediator.register(user3);
mediator.register(user4);

user1.send("Hi all i'm user1");
user1.send("Hi user3");
user2.send("talk in private", user1);
user4.send("get a room!", user1);
user3.send("Hi, i'm here", user1);

mediator2.js

// with constructor functions pattern
function Client(name) {
  this.name = name;
  this.mediator = null;
}

Client.prototype.send = function(message, to) {
  if (!this.mediator) {
    throw ('you need to register to a mediator first')
  }
  this.mediator.send(message, this, to);
}
Client.prototype.receive = function(message, from) {
  console.log(from.name + " to " + this.name + ": " + message);
}

function Mediator() {
  this.clients = {};
}

Mediator.prototype.register = function(client) {
  this.clients[client.name] = client;
  client.mediator = this;
}

Mediator.prototype.send = function(message, from, to) {
  if (to) {
    to.receive(message, from);
  } else {
    for (const key in this.clients) {
      if (this.clients[key] !== from) {
        this.clients[key].receive(message, from);
      }
    }
  }
}


var user1 = new Client("user1");
var user2 = new Client("user2");
var user3 = new Client("user3");
var user4 = new Client("user4");

var mediator = new Mediator();
mediator.register(user1);
mediator.register(user2);
mediator.register(user3);
mediator.register(user4);

user1.send("Hi all i'm user1");
user1.send("Hi user3");
user2.send("talk in private", user1);
user4.send("get a room!", user1);
user3.send("Hi, i'm here", user1);