Travel Agency

function travelAgency(input) {
    let town = input[0];
    let pack = input[1];
    let vip = input[2]
    let days = Number(input[3]);
    if (days > 7) {
        days--;
    }

    let total = days

    if ((town === "Bansko" || town === "Borovets" || town === "Varna" || town === "Burgas") &&
        (pack === "noEquipment" || pack === "withEquipment" || pack === "noBreakfast" || pack === "withBreakfast")) {
        if (days < 1) {
            console.log("Days must be positive number!");
        } else {
            if (town === "Bansko" || town === "Borovets") {
                if (pack === "withEquipment") {
                    total *= 100;
                    if (vip == "yes") {
                        total *= 0.90;
                    }
                } else {
                    total *= 80
                    if (vip == "yes") {
                        total *= 0.95;
                    }
                }
            } else {
                if (pack == "withBreakfast") {
                    total *= 130;
                    if (vip == "yes") {
                        total *= 0.88;
                    }
                } else {
                    total *= 100
                    if (vip == "yes") {
                        total *= 0.93;
                    }
                }
            }
            console.log(`The price is ${total.toFixed(2)}lv! Have a nice time!`)
        }
    } else {
        console.log("Invalid input!");
    }
}

РЕШЕНИЕ С ТЕРНАРЕН ОПЕРАТОР:

function travelAgency(input) {
    let town = input[0];
    let pack = input[1];
    let vip = input[2]
    let days = Number(input[3]);
    days -= days > 7 ? 1 : 0;

    let total = (town === "Bansko" || town === "Borovets" ?
        (pack === "withEquipment" ? 100 * (vip == "yes" ? 0.90 : 1) :
            pack === "noEquipment" ? 80 * (vip == "yes" ? 0.95 : 1) : 0) :
        town === "Varna" || town === "Burgas" ? (pack == "withBreakfast" ? 130 * (vip == "yes" ? 0.88 : 1) :
            pack === "noBreakfast" ? 100 * (vip == "yes" ? 0.93 : 1) : 0) : 0) * days;

    console.log(days < 1 ? "Days must be positive number!" : total === 0 ? "Invalid input!" : `The price is ${total.toFixed(2)}lv! Have a nice time!`);
}