Roman Numeral in Typescript

Welcome to the Roman Numeral in Typescript page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

// Roman Numeral Conversion

const romanNumeralValues = {
  "I": 1,
  "V": 5,
  "X": 10,
  "L": 50,
  "C": 100,
  "D": 500,
  "M": 1000
};

function romanNumeralConversion(str?: string) {

  // Check for blank input
  if (str === undefined) {
    return "Usage: please provide a string of roman numerals";
  }

  // Check for empty string
  if (str === "") {
    return 0;
  }

  // Get valid characters
  const validValues = Object.keys(romanNumeralValues)

  // Check for invalid characters
  for (let i = 0; i < str.length; i++) {
    const char = str.charAt(i)
    if (char === undefined || validValues.indexOf(char) === -1) {
      return "Error: invalid string of roman numerals";
    }
  }

  // Calculating result (adding/subtracting)
  // 
  // Note: next will be undefined for the last element, it'll
  // still work though since 'any number' < undefined will
  // be false ... hacky - but works!
  //
  // Note 2: This does not account for wrongly formatted
  // Roman Numerals like IIIIIIIIIX

  let answer = 0;
  for (let i = 0; i < str.length; i++) {
    const curr = romanNumeralValues[str.charAt(i)];
    const next = romanNumeralValues[str.charAt(i+1)];
    if (curr < next) {
      answer -= curr;
    } else {
      answer += curr;
    }
  }

  return answer;
}


// CLI use needs to have node.js installed
// Run like so:
//   node roman-numeral.js IIIIIIXXVXIV


// Process arguments from CLI
const args = process.argv.slice(2);

if (args.length < 1) {
  console.error("Usage: please provide a string of roman numerals");
} else {
  console.info(romanNumeralConversion(args[0]))
}

Roman Numeral in Typescript was written by:

• Antonino Bertulla

If you see anything you'd like to change or update, please consider contributing.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

No 'How to Run the Solution' section available. Please consider contributing.