Roman Numeral Converter

cr-numeral is a lightweight and versatile npm package designed to effortlessly convert numbers to Roman numerals and vice versa. Whether you're building educational tools, historical applications, or need Roman numeral functionality in your project, cr-numeral provides a simple and efficient solution.

Installing

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Using npm:

``

bash

$ npm install cr-numeral





Using bower:

bash

$ bower install cr-numeral





Using yarn:

bash

$ yarn add cr-numeral





Using pnpm:

bash

$ pnpm add cr-numeral





Using bun:

bash

$ bun add cr-numeral





Once the package is installed, you can import the library using

import or require

 approach:

js

import {

  convertRomanToNumber,

  convertNumberToRoman,

  numeralValidation,

} from "cr-numeral";





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Using jsDelivr CDN (ES5 UMD browser module):

html





Using unpkg CDN:

html





Usage



> [!NOTE]

> THe NuMErAL arGUmeNtS aRe CAse-INsenSITIVe



#### Browser

javascript

// Convert Number to Roman Numeral

String.convertNumberToRoman(2025);

("MMXXV");



// Convert Roman Numeral to Number

String.convertRomanToNumber("MMXXI");

("2021");



// Validate Roman Numeral

const validator = String.numeralValidation("MMX3X2cV8b");

validator.isStrictValid; // false

validator.isLooseValid; // true

validator.isValid; // true





#### Quick use

js

const {

  convertNumberToRoman: cnr,

  convertRomanToNumber: crn,

  numeralValidation: nvl,

} = require("cr-numeral");

// OR

const cnr = require("cr-numeral").convertNumberToRoman;

const crn = require("cr-numeral").convertRomanToNumber;

const nvl = require("cr-numeral").numeralValidation;



const number = 2021;

const numeral = "MMMXXV"; // Case-insensitive



const toRoman = cnr(number);

const toNumber = crn(numeral);

const validateNumeral = nvl(numeral);



console.log(toRoman, toNumber, validateNumeral);





Features



- Convert a Number to a Roman Numeral

convertNumberToRoman(number)



- Convert a Roman Numeral to a Number

convertRomanToNumber("Numeral")



- Validate a Roman Numeral input

numeralValidation("Numeral")





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#### Converting a Number to Roman Numeral



Converting a number to a Roman numeral involves mapping numbers to specific Roman symbols (e.g., I, V, X, L, C, D, M).

javascript

> const { convertNumberToRoman } = require('cr-numeral');

// OR

> const convertNumberToRoman = require('cr-numeral').convertNumberToRoman;



> convertNumberToRoman(2021);

"MMXXI"



> convertNumberToRoman(-2021); // Can not convert a negative number or zero

"Can not convert Zero or negative numbers!!!"



> convertNumberToRoman("na256m");

"You must provide only valid numbers!!!"



> convertNumberToRoman(false);

"Cannot use Boolean values!!!"



> convertNumberToRoman(true);

"Cannot use Boolean values!!!"





#### Converting Roman Numeral to a Number



Converting a Roman numeral to a number involves translating each Roman symbol (I, V, X, L, C, D, M) to its numeric value and summing them.

javascript

> const { convertRomanToNumber } = require('cr-numeral');

// OR

> const convertRomanToNumber = require('cr-numeral').convertRomanToNumber;



> convertRomanToNumber("MMXXI");

"2021"



> convertRomanToNumber("na256m");

"Provide a valid roman character!!!"

"Cause these are invalid roman numerals : [ N,A,2,5,6 ]"



> convertRomanToNumber(6355);

"You must provide only valid strings!!!"



> convertRomanToNumber(false);

"Cannot use Boolean values!!!"



> convertRomanToNumber(true);

"Cannot use Boolean values!!!"





#### Validating Roman numeral string



Validating a Roman numeral string ensures it follows the correct rules for Roman numerals.



- Check if the string contains only valid symbols.

- Verify no invalid characters or digits are included.

- Confirm symbols are and can be processed.

javascript

> const { numeralValidation } = require('cr-numeral');

// OR

> const { numeralValidation } = require('cr-numeral');



> const {  isInputEmpty,

  inputCount,

  isStrictValid,

  isLooseValid,

  hasInvalidNumerals,

  hasDigits,

  isValid,

  invalidNumeralCount,

  digitsCount,

  invalidInputsCount,

  invalidDigits,

  invalidNumeralStrings,

  validNumeralValues

} = numeralValidation("MMX3X2xcV8b");



// Only valid if there are no invalid inputs and at least one valid numeral

console.log(isStrictValid) // false



// Valid if there is at least one valid numeral

console.log(isLooseValid) // true



// Overall validity and if input can be processed

console.log(isValid) // true





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-

isInputEmpty

 - Checks if the input is empty



-

inputCount

 - How many input characters were provided



-

hasInvalidNumerals

 - Checks if there are any invalid characters



-

hasDigits

 - Checks if there are any digits



-

invalidNumeralCount

 - How many invalid characters were found in total



-

digitsCount

 - How many digits were found in total



-

invalidInputsCount

 - How many invalid inputs were found in total



-

invalidDigits

 - Lists of invalid digits



-

invalidNumeralStrings

 - Lists of invalid numeral strings



-

validNumeralValues

 - Lists of valid numeral values



Changelog



Tests



To run the test suite, first install the dependencies, then run

npm test

bash

$ npm install

$ npm run test

Contact :rocket:

Email

- If you are looking to get ahold of me, you can send me an Email : Naphtali Duniya

Social Media

- Instagram : Naphtali Duniya

* Via Twitter : Naphtali Duniya

Telephone

- Call +44 (0)787 100 2267

Donate

I maintain this project in my free time, if it helped you please support my work via Revolut, thanks a lot!

License