From d5b6dc31cdfce87b32d7f1e106449955a94e0f25 Mon Sep 17 00:00:00 2001
From: Corey Martin <coreyn.martin@gmail.com>
Date: Thu, 16 Jan 2025 11:19:09 -0800
Subject: [PATCH] [core] Hide units by default when unit is current locale
 currency unit (#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           | 11 +++++++++++
 packages/ui/src/components/CurrencyAmount.tsx |  5 +++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/packages/core/src/utils/currency.ts b/packages/core/src/utils/currency.ts
index 37e64c71..4e9c658b 100644
--- a/packages/core/src/utils/currency.ts
+++ b/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}`;
diff --git a/packages/ui/src/components/CurrencyAmount.tsx b/packages/ui/src/components/CurrencyAmount.tsx
index efad9500..9914ff09 100644
--- a/packages/ui/src/components/CurrencyAmount.tsx
+++ b/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;