[core] Hide units by default when unit is current locale currency uni…

…t (#14909)

Also start defaulting to non lowercase, non plural appended units
everywhere. This should have already been the default.

GitOrigin-RevId: 4f5db9dc9098b257daaf54ca14220397691cd653

packages/core/src/utils/currency.ts

@@ -577,6 +577,9 @@ const defaultOptions = {
 export type AppendUnitsOptions = {
   plural?: boolean | undefined;
   lowercase?: boolean | undefined;
+  /* Default behavior for built in toLocaleString is to not show the unit when it's
+     the default unit in the locale (when using default currencyDisplay). We'll do the same. */
+  showForCurrentLocaleUnit?: boolean | undefined;
 };
 
 type FormatCurrencyStrOptions = {
@@ -675,6 +678,14 @@ export function formatCurrencyStr(
   }
 
   if (options?.appendUnits) {
+    const localeCurrencyCode = localeToCurrencyCode(currentLocale);
+    if (
+      unit === localeCurrencyCode &&
+      !options.appendUnits.showForCurrentLocaleUnit
+    ) {
+      return formattedStr;
+    }
+
     const unitStr = abbrCurrencyUnit(unit);
     const unitSuffix = options.appendUnits.plural && num > 1 ? "s" : "";
     const unitStrWithSuffix = `${unitStr}${unitSuffix}`;

packages/ui/src/components/CurrencyAmount.tsx

@@ -65,8 +65,9 @@ export function CurrencyAmount({
       ? undefined
       : showUnits === true
       ? ({
-          plural: true,
-          lowercase: true,
+          plural: false,
+          lowercase: false,
+          showForCurrentLocaleUnit: false,
         } as const)
       : showUnits;