Value of a String JS Fundamentals

function valueOfAString(data) {
    let string = data[0];
    let command = data[1];
    let lowerCaseSum = 0;
    let upperCaseSum = 0;

    for (let i = 0; i < string.length; i++) {
        let code = string.charCodeAt(i);
        if (code >= 65 && code <= 90) {
            upperCaseSum += code;
        } else if (code >= 97 && code <= 122) {
            lowerCaseSum += code;
        }
    }
    if (command === 'LOWERCASE') {
        console.log(`The total sum is: ${lowerCaseSum}`);
    } else {
        console.log(`The total sum is: ${upperCaseSum}`);
    }
}