RomanNumerals Problem

/**
 * @param {string} s
 * @return {number}
 */
var romanToInt = function(s) {
    
    let sum = 0;
    let remainingS = s;
    
    const symbols = {
                      'IV':4,
                      'IX':9,
                      'XL':40,
                      'XC':90,
                      'CD':400,
                      'CM':900,
                      'I': 1,
                      'V': 5,
                      'X': 10,
                      'L': 50,
                      'C': 100,
                      'D': 500,
                      'M': 1000,

                    };
    
    Object.keys(symbols).map((sym) => {
        while ()
    })
   
    
    return sum;
    
};

console.log(romanToInt('IV'))