(Kay Albito) Coding Challenge - textDollar.js

const onesIndex = {
  '0': '',
  '1': 'One',
  '2': 'Two',
  '3': 'Three',
  '4': 'Four',
  '5': 'Five',
  '6': 'Six',
  '7': 'Seven',
  '8': 'Eight',
  '9': 'Nine',
};

const tensIndex = {
  '0': '',
  '2': 'Twenty',
  '3': 'Thirty',
  '4': 'Forty',
  '5': 'Fifty',
  '6': 'Sixty',
  '7': 'Seventy',
  '8': 'Eighty',
  '9': 'Ninety',
};

const elevenToNineteen = {
  '11': 'Eleven',
  '12': 'Twelve',
  '13': 'Thirteen',
  '14': 'Fourteen',
  '15': 'Fifteen',
  '16': 'Sixteen',
  '17': 'Seventeen',
  '18': 'Eighteen',
  '19': 'Nineteen',
};

function joinText (target, unit) {
  let result = '';
  for (let i = unit.length - 1; i >= 0; i--) {
    result = result.concat(target[unit[i]]);
  }
  return result == 0 ? 'Zero' : result == 'One' ? result.concat('Dollar') : result.concat('Dollars');
}

function transliterateTens (target, index, unit) {
  if (target[index] == 1) {
    if (target[index - 1] == 0) {
      if (index > 3) {
        target[index] = 'TenThousand';  
      } else {
        target[index] = 'Ten';
      }
    } else {
      const tensNumber = target[index].concat(target[index - 1]);
      target[index] = elevenToNineteen[tensNumber].concat(unit);
      target[index - 1] = 0;
    }
  } else {
    const tensNumber = target[index];
    const onesNumber = target[index - 1];
    target[index] = tensIndex[tensNumber];
    target[index - 1] = onesIndex[onesNumber].concat(unit);
  }
}

function transliterateHundreds (target, index) {
  if (target[index] != 0) {
    const hundredsNumber = target[index];
    target[index] = onesIndex[hundredsNumber].concat('Hundred');
  } 
}

function textDollar (number) {
  const integerMap = {};
  const reverseNumber = number.toString().split("").reverse().join("");
  for (let i = 0; i < reverseNumber.length; i++) {
    integerMap[i] = reverseNumber[i];
  }

  if (1 in integerMap) {
    transliterateTens(integerMap, 1, '');
  } else {
    const onesNumber = integerMap[0];
    integerMap[0] = onesIndex[onesNumber];
  }

  if (2 in integerMap) {
    transliterateHundreds(integerMap, 2);
  }

  if (3 in integerMap) {
    if (4 in integerMap) {
      if (integerMap[3] == 0 && integerMap[4] == 0) {
        integerMap[3] == '';
        integerMap[4] == '';
      } else {
        transliterateTens(integerMap, 4, 'Thousand');
      }
    } else {
      const thousandsNumber = integerMap[3];
      integerMap[3] = onesIndex[thousandsNumber].concat('Thousand');
    }
  }

  if (5 in integerMap) {
    transliterateHundreds(integerMap, 5);
  }

  if (6 in integerMap) {
    if (7 in integerMap) {
      transliterateTens(integerMap, 7, 'Million');
    } else {
      const millionsNumber = integerMap[6];
      integerMap[6] = onesIndex[millionsNumber].concat('Million');
    }
  }

  if (8 in integerMap) {
    transliterateHundreds(integerMap, 8);
  }

  const unitsToBeAdded = [];
  for (let unit in integerMap) {
    if (integerMap[unit] != '0') {
      unitsToBeAdded.push(unit);
    }
  }

  return joinText(integerMap, unitsToBeAdded);
}

console.log(textDollar(0));
console.log(textDollar(1));
console.log(textDollar(9)); 
console.log(textDollar(10));
console.log(textDollar(11));
console.log(textDollar(20));
console.log(textDollar(99));
console.log(textDollar(100));
console.log(textDollar(111));
console.log(textDollar(999));
console.log(textDollar(1000));
console.log(textDollar(14000));
console.log(textDollar(14444));
console.log(textDollar(99999));
console.log(textDollar(99000));
console.log(textDollar(92013));
console.log(textDollar(90103));
console.log(textDollar(901030));
console.log(textDollar(100000));
console.log(textDollar(111111));
console.log(textDollar(110110));
console.log(textDollar(909909));
console.log(textDollar(999919));
console.log(textDollar(1000000));
console.log(textDollar(1111111));
console.log(textDollar(90932845));
console.log(textDollar(90000800));
console.log(textDollar(900008000));
console.log(textDollar(900000000));