Event PubSub

const events = (function () {
	const topics = {};

	return {
		subscribe(topic, listener) {
			// Create topics object if not yet created
			if (!topics.hasOwnProperty.call(topics, topic)) topics[topic] = [];

			// Add listener to the queue
			const index = topics[topic].push(listener) - 1;

			// Provide handle back for removal of topic
			return {
				remove() {
					delete topics[topic][index];
				},
			};
		},
		publish(topic, info = {}) {
			// If the topic doesn't exist, or there's no listeners in queue, just leave
			if (!topics.hasOwnProperty.call(topics, topic)) return;

			// Cycle through topics queue, fire!
			topics[topic].forEach(item => item(info));
		},
	};
}());

export default events;

Inspired by https://davidwalsh.name/pubsub-javascript