computer storage

//01. Computer Store
function solve(arr) {

    let taxes = 0.20;
    let taxesSum = 0;
    let flag = false;
    let special = 0.90;
    let priceSpecial = 0;
    let prices = 0;

    arr.forEach(x => {
        if (Number(x) && Number(x) > 0) {
            prices += Number(x);

        } else if (Number(x) < 0) {
            console.log(`Invalid price!`);

        } else if (x === 'special') {
            flag = true;
            taxesSum = (prices * taxes);
            priceSpecial = (prices + taxesSum) * (1 - 0.10);

        } else if (x === 'regular' && prices > 0) {
            flag = true;
            taxesSum = (prices * taxes);
            priceSpecial = (prices + taxesSum);
        }
    });

    if (flag) {
        console.log(`Congratulations you've just bought a new computer!`)
        console.log(`Price without taxes: ${prices.toFixed(2)}$`);
        console.log(`Taxes: ${taxesSum.toFixed(2)}$`);
        console.log(`-----------`);
        console.log(`Total price: ${priceSpecial.toFixed(2)}$`);
    } else {
        console.log(`Invalid order!`);
    }
}
// solve([1023,15,-20,-5.50,450,20,17.66,19.30,'regular'])
solve(['regular']);
// solve(['1050','200','450','2','18.50','16.86','special']);
// solve(['1023','15','-20','-5.50','450','20','17.66','19.30', 'regular'])