refactor(money): refactor formatMoney to reuse formatter objects

src/helpers/money.ts

@@ -13,6 +13,14 @@ const getCurrencyFractionLength = (currency: string) => {
 };
 
 export class Money {
+
+    /**
+     * A private property that stores cached instances of `Intl.NumberFormat`
+     * for different locale and currency combinations.
+     * The key is a string representing the locale and currency,
+     * and the value is the corresponding `Intl.NumberFormat` instance.
+     */
+    #cachedFormatters: { [key: string]: Intl.NumberFormat } = {};
     /**
 	 * Formats the Money object based on the provided locale.
 	 *
@@ -33,20 +41,26 @@ export class Money {
 	 * @returns The formatted amount.
 	 */
     formatAmount(amount: number, currency: string, formattedLocale = 'en-US'): string {
-        let formatter;
-        try {
-            formatter = new Intl.NumberFormat(formattedLocale, {
-                style: 'currency',
-                currencyDisplay: 'symbol',
-                currency: currency
-            });
-        } catch (err) {
-            // Fallback to en-US if it's an invalid BCP 47 locale
-            formatter = new Intl.NumberFormat('en-US', {
-                style: 'currency',
-                currencyDisplay: 'symbol',
-                currency: currency
-            });
+        // use the cached formatter if present, to avoid creating a new formatter every time
+        const cacheKey = `${currency}:${formattedLocale}`;
+        let formatter = this.#cachedFormatters[cacheKey];
+        if (!formatter) {
+            // create a new formatter for this currency + locale
+            try {
+                formatter = new Intl.NumberFormat(formattedLocale, {
+                    style: 'currency',
+                    currencyDisplay: 'symbol',
+                    currency: currency
+                });
+            } catch (err) {
+                // Fallback to en-US if it's an invalid BCP 47 locale
+                formatter = new Intl.NumberFormat('en-US', {
+                    style: 'currency',
+                    currencyDisplay: 'symbol',
+                    currency: currency
+                });
+            }
+            this.#cachedFormatters[cacheKey] = formatter;
         }
         amount = this.convertSubunitsToFloat(amount, currency);
         return formatter.format(amount);