From f38adb5e0287b081138f7d0f3d299ec4432b87d2 Mon Sep 17 00:00:00 2001
From: Johannes Loher <johannes.loher@fg4f.de>
Date: Thu, 10 Nov 2022 04:32:52 +0100
Subject: [PATCH] refactor: improve conversion to roman numerals

---
 src/handlebars/handlebars-helpers.ts | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/src/handlebars/handlebars-helpers.ts b/src/handlebars/handlebars-helpers.ts
index dcdde633..07cc2e13 100644
--- a/src/handlebars/handlebars-helpers.ts
+++ b/src/handlebars/handlebars-helpers.ts
@@ -18,29 +18,23 @@ const helpers = {
 };
 
 function toRomanNumerals(number: number): string {
-    return toRomanNumeralsRecurse(number, numerals) ?? "";
+    return [...generateRomanNumerals(number, 0)].join("");
 }
 
-function toRomanNumeralsRecurse(number: number, numerals: number[]): string | undefined {
-    if (number === 0) {
-        return undefined;
-    }
-    const currentNumeral = numerals[0];
-    if (currentNumeral === undefined) {
-        return undefined;
-    }
+function* generateRomanNumerals(number: number, numeralIndex: number): Generator<string> {
+    if (number === 0) return;
+    const currentNumeral = numerals[numeralIndex];
+    if (currentNumeral === undefined) return;
 
     const quotient = number / currentNumeral;
     const remainder = number % currentNumeral;
-    const numberAsNumerals = numeralLookup[currentNumeral]?.repeat(quotient);
-    if (numberAsNumerals === undefined) {
-        return undefined;
-    }
-    const [, ...remainingNumerals] = numerals;
-    return numberAsNumerals + (toRomanNumeralsRecurse(remainder, remainingNumerals) ?? "");
+    const numberAsNumerals = numeralLookup[currentNumeral].repeat(quotient);
+
+    yield numberAsNumerals;
+    yield* generateRomanNumerals(remainder, numeralIndex + 1);
 }
 
-const numeralLookup: Record<number, string> = {
+const numeralLookup = {
     1: "I",
     2: "II",
     3: "III",
@@ -73,4 +67,4 @@ const numeralLookup: Record<number, string> = {
 
 const numerals = [
     1000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,
-];
+] as const;