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fix(roman-numeral-converter): checks for valid input and conversion enhancements

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Validates if numeral values are between 1 and 3999999.
Validates if a roman number is valid.
This commit is contained in:
Carsten Götzinger 2023-04-06 13:55:36 +02:00
parent f350dc19aa
commit 3fe9dc4c0c
3 changed files with 79 additions and 15 deletions
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25
src/tools/roman-numeral-converter/roman-numeral-converter.service.ts
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@ -1,7 +1,21 @@
export const MIN_ARABIC_TO_ROMAN = 1;
export const MAX_ARABIC_TO_ROMAN = 3999999;
export function arabicToRoman(num: number) {
if (num < 1) return '';
if (num < MIN_ARABIC_TO_ROMAN || num > MAX_ARABIC_TO_ROMAN) return '';
const lookup: { [key: string]: number } = {
'<span style="text-decoration: overline">M</span>': 1000000,
'<span style="text-decoration: overline">CM</span>': 900000,
'<span style="text-decoration: overline">D</span>': 500000,
'<span style="text-decoration: overline">CD</span>': 400000,
'<span style="text-decoration: overline">C</span>': 100000,
'<span style="text-decoration: overline">XC</span>': 90000,
'<span style="text-decoration: overline">L</span>': 50000,
'<span style="text-decoration: overline">XL</span>': 40000,
'<span style="text-decoration: overline">X</span>': 10000,
'<span style="text-decoration: overline">IX</span>': 9000,
'<span style="text-decoration: overline">V</span>': 5000,
'<span style="text-decoration: overline">IV</span>': 4000,
M: 1000,
CM: 900,
D: 500,
@ -26,7 +40,16 @@ export function arabicToRoman(num: number) {
return roman;
}
const ROMAN_NUMBER_REGEX = new RegExp(/^M{0,3}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$/);
export function isValidRomanNumber(romanNumber: string) {
return ROMAN_NUMBER_REGEX.test(romanNumber);
}
export function romanToArabic(s: string) {
if (!isValidRomanNumber(s)) {
return null;
}
const map: { [key: string]: number } = { I: 1, V: 5, X: 10, L: 50, C: 100, D: 500, M: 1000 };
return [...s].reduce((r, c, i, s) => (map[s[i + 1]] > map[c] ? r - map[c] : r + map[c]), 0);
}