roman-numerals-third

//small conversion array, still somewhat ugly helper logic, simple loop in main

const conversions = [
  {nextLetter: 'X', midLetter: 'V', letter: 'I'},
  {nextLetter: 'C', midLetter: 'L', letter: 'X'},
  {nextLetter: 'M', midLetter: 'D', letter: 'C'}
];

function convert(n, legend) {
  let origNum = Number(n);
  if(origNum === 0) { 
    return '';
  } else if(origNum > 0 && origNum < 4) {
    return legend.letter.repeat(origNum);
  } else if(origNum === 4) {
    return legend.letter + legend.midLetter;
  } else if(origNum === 5) {
    return legend.midLetter;
  } else if(origNum > 5 && origNum < 9) {
    return legend.midLetter + legend.letter.repeat(origNum - 5); 
  } else {
    return legend.letter + legend.nextLetter;
  }
}

function convertToRoman(num) {
  const numArray = String(num).split('');
  const len = numArray.length;
  let ansArr = [];
  
  for(let i = 0; i < len; i += 1) {
    let toPush;
    if(len === 4 && i === 0) {
      toPush = 'M'.repeat(numArray[i]);
    } else {
      let convMatrix = conversions[len - 1 - i];
      toPush = convert(numArray[i], convMatrix);
    }
    ansArr.push(toPush);
  }
  return ansArr.join('');
}