Mixed-Messages project

I would like an honest review over my code. Does it need to be more advanced or is it someway I can improve it.
It took me around 5 hours to complete, but I managed to do it.

const messages = {
    _inspirational: ['You are great', 'We are awesome', 'They\'re amazing', 'Today will be super'],
    _joke: ['The dogs getting fat', 'She\'s a bad little girl', 'Don\'t act ugly', 'Your friends are clumsy'],
    _zodiac: ['Your sign is a capricorn', 'Your sign is a leo', 'Your sign is a virgo', 'Your sign is a scorpio', 'Your sign is a taurus']

const randomMess = () => {
    for (const key of Object.keys(messages)) {
        let randomIndex = Math.floor(Math.random() * messages[key].length);