refactor: split currency and key/metal formatting into separate units

this simplifies functions and tests, and will make currency optional/variable later

src/content/utils/currency.ts

@@ -0,0 +1,8 @@
+import { conversion_ref_usd } from '../config';
+
+export function convertTF2PriceToUSD(keys: number, metal: number, keyPrice: number): number {
+	const pureMetal = (keys * keyPrice) + metal;
+
+	// Round price up to nearest cent
+  return Math.ceil(pureMetal * conversion_ref_usd * 100) / 100
+}

src/content/utils/formatting.ts

@@ -7,7 +7,6 @@ function toFixed(num: number, fixed: number) {
 }
 
 export function formatPrice(keys: number, metal: number, keyPrice: number, locale: string = 'en') {
-	const pureMetal = (keys * keyPrice) + metal;
 	const formattedKeys = +(keys + (metal / keyPrice)).toFixed(2)
 
 	var output: string = ''
@@ -16,13 +15,6 @@ export function formatPrice(keys: number, metal: number, keyPrice: number, local
 	} else {
 		output += $T("%@ ref").replace('%@', (+toFixed(metal, 2)).toLocaleString(locale))
 	}
-	const currencyFormatter = new Intl.NumberFormat(locale, {
-		minimumFractionDigits: 2,
-		maximumFractionDigits: 2,
- 	});
 
-	// Round price up to nearest cent
- 	const price = Math.ceil(pureMetal * conversion_ref_usd * 100) / 100
-	output += ` (US$${currencyFormatter.format(price)})`
 	return output;
 }