From ab6b93b53a46a658d713ee57616c06aeaf4de96b Mon Sep 17 00:00:00 2001
From: Zack Sunderland <SimplyComplexable@gmail.com>
Date: Tue, 11 Apr 2023 07:07:06 -0600
Subject: [PATCH] Allow for falsey default values (#1021)

Co-authored-by: zsunderland <zsunderland@traeger.com>
---
 __tests__/useTranslation.test.js | 30 ++++++++++++++++++++++++++----
 src/transCore.tsx                | 13 +++++++++++--
 2 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/__tests__/useTranslation.test.js b/__tests__/useTranslation.test.js
index e2466d5e..0264b6ff 100644
--- a/__tests__/useTranslation.test.js
+++ b/__tests__/useTranslation.test.js
@@ -1185,7 +1185,7 @@ describe('useTranslation', () => {
           { count: 3 },
           {
             default: {
-              example: 'This is a default translation with a count: {{count}}'
+              example: 'This is a default translation with a count: {{count}}',
             },
             returnObjects: true,
             fallback: 'ns:no-translation2',
@@ -1210,9 +1210,7 @@ describe('useTranslation', () => {
           'ns:no-translation',
           { count: 3 },
           {
-            default: [
-              'This is a default translation with a count: {{count}}'
-            ],
+            default: ['This is a default translation with a count: {{count}}'],
             returnObjects: true,
             fallback: 'ns:no-translation2',
           }
@@ -1222,6 +1220,30 @@ describe('useTranslation', () => {
 
       const expected = 'This is a default translation with a count: 3'
 
+      const { container } = render(
+        <I18nProvider lang="en" namespaces={{}}>
+          <Inner />
+        </I18nProvider>
+      )
+      expect(container.textContent).toBe(expected)
+    })
+    test('should return falsey default values', () => {
+      const Inner = () => {
+        const { t } = useTranslation()
+        const text = t(
+          'ns:no-translation',
+          { count: 3 },
+          {
+            default: undefined,
+            returnObjects: true,
+            fallback: 'ns:no-translation2',
+          }
+        )
+        return <>{`${text}`}</>
+      }
+
+      const expected = 'undefined'
+
       const { container } = render(
         <I18nProvider lang="en" namespaces={{}}>
           <Inner />
diff --git a/src/transCore.tsx b/src/transCore.tsx
index fc86c3a6..3f5a40aa 100644
--- a/src/transCore.tsx
+++ b/src/transCore.tsx
@@ -99,8 +99,17 @@ export default function transCore({
       }
     }
 
-    if (empty && options?.default && !fallbacks?.length) {
-      return interpolateUnknown(options.default, query)
+    if (
+      empty &&
+      options &&
+      // options.default could be a nullish value so check that the property exists
+      options.hasOwnProperty('default') &&
+      !fallbacks?.length
+    ) {
+      // if options.default is falsey there's no reason to do interpolation
+      return options.default
+        ? interpolateUnknown(options.default, query)
+        : options.default
     }
 
     // no need to try interpolation