roman.js

"use strict";
const toRoman = (nmb, logOutput) => {
    const num = Number(nmb);
    if (isNaN(num)) {
        console.error('You provided not a numeric value. Please double check the value.');
        return '';
    }
    if (num < 0) {
        console.error('Please provide an integer larger than -1');
        return '';
    }
    if (num === 0) {
        if (!!logOutput)
            console.log('NULLA');
        return 'NULLA';
    }
    if (num > 3999) {
        console.error('Please provide an integer that is between 1 and 3999');
        return '';
    }
    if (!Number.isInteger(num)) {
        console.error('Provided number should be an integer, and should be between 1 and 3999');
        return '';
    }
    const getValues = (num, a, b, c) => {
        const values = ['', `${a}`, `${a}${a}`, `${a}${a}${a}`, `${a}${b}`, `${b}`, `${b}${a}`, `${b}${a}${a}`, `${b}${a}${a}${a}`, `${a}${c}`, `${c}`];
        return values[num];
    };
    const numStr = num.toString().split('').reverse();
    const doneArray = [];
    numStr.forEach((item, index) => {
        const level = index;
        switch (level) {
            case 0:
                doneArray.push(getValues(Number(item), 'i', 'v', 'x'));
                break;
            case 1:
                doneArray.push(getValues(Number(item), 'x', 'l', 'c'));
                break;
            case 2:
                doneArray.push(getValues(Number(item), 'c', 'd', 'm'));
                break;
            case 3:
                doneArray.push(getValues(Number(item), 'm', '', ''));
                break;
        }
    });
    const result = doneArray.reverse().join('').toUpperCase();
    if (!!logOutput)
        console.log(result);
    return result;
};
toRoman(-1.2, true);
toRoman(0, true);
toRoman('1', true);
toRoman('0', true);
toRoman('3', true);
toRoman(10, true);
toRoman(999, true);
toRoman(1000, true);
toRoman(2999, true);
toRoman(3000, true);
toRoman(3500, true);
toRoman(3999, true);
toRoman(4000, true);
toRoman('abc', true);