Yamo93

const subscribers = {
  onUserUpdate: [callbackFunction, anotherCallbackFunction],
  onUserLogin: [callbackFunction, anotherCallbackFunction]
};

Yamo93

function subscribe(eventName, callback) {
  if (!Array.isArray(subscribers[eventName])) {
    subscribers[eventName] = []
  }
  subscribers[eventName].push(callback);
  const index = subscribers[eventName].length - 1;
  return () => {
    subscribers[eventName].splice(index, 1);
  }
}

Yamo93

function unsubscribe(eventName) {
  delete subscribers[eventName];
}

Yamo93

function publishSubscribe() {
  const subscribers = {};
  function subscribe(eventName, callback) {
    if (!Array.isArray(subscribers[eventName])) {
      subscribers[eventName] = [];
    }
    subscribers[eventName].push(callback);
  }
  function publish(eventName, data) {
    if (!Array.isArray(subscribers[eventName])) {

Yamo93

function publish(eventName, data) {
  if (!Array.isArray(subscribers[eventName])) {
    return;
  }
  subscribers[eventName].forEach(callback => {
    if (typeof callback === 'function') {
      callback(data);
    }
  })
}

Yamo93

function subscribe(eventName, callback) {
  if (!Array.isArray(subscribers[eventName])) {
    subscribers[eventName] = [];
  }
  subscribers[eventName].push(callback);
}