rendezvous with cassidoo 6/16

sortMonarchs.js

// Given an array of strings representing the names of monarchs 
// and their ordinal numbers, write a function that returns the 
// list of names sorted first by name and then by their ordinal 
// value (in Roman numerals), in ascending order.


function sortMonarchs(names) {
  const romanToInt = (roman) => {
    const romanMap = {
      I: 1,
      V: 5,
      X: 10,
      L: 50,
      C: 100,
      D: 500,
      M: 1000
    };

    let total = 0;

    for (let i = 0; i < roman.length; i++) {
      const currentVal = romanMap[roman[i]];
      const nextVal = romanMap[roman[i + 1]];

      if (nextVal && currentVal < nextVal) {
        total -= currentVal;
      } else {
        total += currentVal;
      }
    }
    return total;
  };

  return names.sort((a, b) => {
    const [aName, aOrdinal] = a.split(" ");
    const [bName, bOrdinal] = b.split(" ");

    const nameComparison = aName.localeCompare(bName);
    
    if (nameComparison !== 0) {
      return nameComparison;
    }

    const aValue = romanToInt(aOrdinal);
    const bValue = romanToInt(bOrdinal);

    return aValue - bValue;
  });
}