romanToInt.js

const romanToInt = function (s) {
    let total = 0;
    for (let i = 0; i < s.length;) {
        let currentVal = valueMap[s[i]];
        if (i === s.length - 1) {
            total += currentVal;
            break;
        }
        let nextVal = valueMap[s[i + 1]];
        if (currentVal < nextVal) {
            total += nextVal - currentVal;
            i += 2;
        } else {
            total += currentVal;
            i += 1;
        }
    }
    return total
};


const valueMap = {
    "I": 1,
    "V": 5,
    "X": 10,
    "L": 50,
    "C": 100,
    "D": 500,
    "M": 1000
}