Simple Observer Pattern Again

example.js

var bus = {
	messages: {},
	on(message, callback) {
		if (this.messages[message] === undefined) {
			this.messages[message] = [];
		}
	this.messages[message].push(callback)
    },
	emit(message, data) {
		if (this.messages[message] !== undefined) {
			this.messages[message].forEach((callback) => {
				callback(data)
            })
        }
    }
}

bus.on('something-happened', (data) => {
	console.log('Que pasa', data)
});

bus.on('something-happened', () => {
	console.log('Que pasa again')
});

bus.emit('something-happened', 'hombre')