app.js

let people = document.getElementById('people');
let people_less = document.getElementById('people_less');
let people_more = document.getElementById('people_more');

let people_index = 4;

people_less.addEventListener('click', () => {
    people_index -= 1;

    if (people_index <= 0) {
        people_index = 1;
        people.value = people_index + ' People';
    } else {
        people.value = people_index + ' People';
    }
})

people_more.addEventListener('click', () => {
    people_index += 1;

    if (people_index >= 4) {
        people_index = 4;
        people.value = people_index + ' People';
    } else {
        people.value = people_index + ' People';
    }
})

let checkin_data = document.getElementById('checkin_data');
let checkin = document.getElementById('checkin');


checkin.addEventListener('change', () => {
    let checkin_value = checkin.value;
    // console.log(checkin_value);

    let dates = new Date(checkin_value);
    let dates2 = new Date();
    const week = ['Sun', 'Mon', 'Thu', 'Wed', 'Thu', 'Fri', 'Sat']
    let day = week[dates.getDay()];
    // console.log(day)

    let date = checkin_value.slice(8, 10);
    // console.log(date);

    let months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

    let month = months[dates.getMonth()];
    // console.log(month);

    if (dates < dates2) {
        console.log('No Date');
    } else {
        checkin_data.innerText = day + ', ' + date + ' ' + month;
    }
})