Simple Event Bus (ES6) < 20 lines

SimpleEventBus.js

let bus = {
	messages: {},
	on(message, callback) {
		if (!this.messages[message]) {
			this.messages[message] = [];
		}
		if (typeof callback === 'function') {
			this.messages[message].push(callback);
		}
	},
	emit(message) {
		if (this.messages[message]) {
			this.messages[message].forEach((func) => {
				func();
			});
		}
	}
}