LongestDynasty.js

const dynastyReign = [
  { 'San Dynasty': 'MXLI' },
  { 'Viloria Dynasty': 'MCCCIIII' },
  { 'Tan Dynasty': 'MCCCXCVIII' },
  { 'Bon Dynasty': 'MCDXLV' },
  { 'Maiko Dynasty': 'MDCLXIV' },
  { 'Paul Dynasty': 'MCMXLIX' },
  { 'Andre Dynasty': 'MMMXICX' },
];

function longestDynasty (dynastyReign) {
  if (dynastyReign.length < 1) return 'No Data';

  const filtered = dynastyReign
    .filter(y => convertYear(Object.values(y).toString()) !== null)
  const fValues = filtered
    .map(el => convertYear(Object.values(el).toString()))

  let reign = 0;
  let max = 0;
  let temp = 0;
  for (let i = 1; i < fValues.length; i++) {
    temp = Math.abs(fValues[i] - fValues[i - 1])
    if (temp > max) {
      max = temp
      reign = i
    }
  }
  return filtered[reign];

}

function convertYear (year) {
  let y = 0;
  if (typeof y === 'undefined' || y === null) return y;

  let regex = new RegExp('^M{0,3}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$');
  if (!regex.test(year)) return null;

  let romanMap = new Map();
  romanMap.set('I', 1);
  romanMap.set('V', 5);
  romanMap.set('X', 10);
  romanMap.set('L', 50);
  romanMap.set('C', 100);
  romanMap.set('D', 500);
  romanMap.set('M', 1000);

  let l = year.length;
  for (var i = 0; i < l; i++) {
    if (romanMap.get(year.charAt(i)) < romanMap.get(year.charAt(i + 1))) {
      y -= romanMap.get(year.charAt(i))
    } else {
      y += romanMap.get(year.charAt(i))
    }
  }

  return y;
}

console.log(longestDynasty(dynastyReign));

SalesProblem.js

const productProfitArray = [
  { "ProductA": -75 },
  { "ProductB": -70 },
  { "ProductC": 98 },
  { "ProductD": 5 },
  { "ProductE": -88 },
  { "ProductF": 29 },
];

function topProduct (productProfitArray) {
  const length = productProfitArray.length;
  if (length < 1) return "No Data";

  let values = [];
  productProfitArray.forEach(e => {
    values.push(Number(Object.values(e)))
  });

  const v = values.sort((b, a) => { return b - a; })[length - 1];

  return productProfitArray.find(el => Number(Object.values(el)) === v);
}

function bottomProduct (productProfitArray) {
  const length = productProfitArray.length;
  if (length < 1) return "No Data";

  let values = [];
  productProfitArray.forEach(e => {
    values.push(Number(Object.values(e)))
  });

  const v = values.sort((b, a) => { return b - a; })[0]

  return productProfitArray.find(el => Number(Object.values(el)) === v);
}

function zeroProfitProduct (productProfitArray) {
  const length = productProfitArray.length;
  if (length < 1) return "No Data";

  let values = [];
  productProfitArray.forEach(e => {
    values.push(Number(Object.values(e)))
  });

  const v = values.reduce((accumulator, currentValue) =>
        accumulator === 0 ? currentValue :
        currentValue > 0 && currentValue <= Math.abs(accumulator) ? currentValue :
        currentValue < 0 && -currentValue < Math.abs(accumulator) ? currentValue : accumulator
    , 0)

  return productProfitArray.find(el => Number(Object.values(el)) === v)
}


const topProductValue = topProduct(productProfitArray);
const bottomProductValue = bottomProduct(productProfitArray);
const zeroProfitProductValue  = zeroProfitProduct(productProfitArray);

console.log(topProductValue);
console.log(bottomProductValue);
console.log(zeroProfitProductValue);