From 4fe470a2f0d04e416318f30aa48de5a85be337f2 Mon Sep 17 00:00:00 2001
From: halouvi <tal.harouvi@honeybook.com>
Date: Mon, 15 Aug 2022 11:28:31 +0300
Subject: [PATCH 1/2] reset `t` when `keyPrefix` changes

---
 src/useTranslation.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/useTranslation.js b/src/useTranslation.js
index efc6e1f7..33a97e10 100644
--- a/src/useTranslation.js
+++ b/src/useTranslation.js
@@ -101,7 +101,7 @@ export function useTranslation(ns, props = {}) {
       setT(getT);
     }
     isInitial.current = false;
-  }, [i18n]); // re-run when i18n instance was replaced
+  }, [i18n, keyPrefix]); // re-run when i18n instance or keyPrefix were replaced
 
   const ret = [t, i18n, ready];
   ret.t = t;

From aef6a378175d6293bf3f829a05573824b2473ae3 Mon Sep 17 00:00:00 2001
From: halouvi <tal.harouvi@honeybook.com>
Date: Mon, 15 Aug 2022 12:13:59 +0300
Subject: [PATCH 2/2] add test for dynamic `keyPrefix`

---
 test/useTranslation.spec.js | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/test/useTranslation.spec.js b/test/useTranslation.spec.js
index fb98e214..152d43b5 100644
--- a/test/useTranslation.spec.js
+++ b/test/useTranslation.spec.js
@@ -115,15 +115,24 @@ describe('useTranslation', () => {
   });
 
   describe('key prefix', () => {
-    i18nInstance.addResource('en', 'translation', 'deeply.nested.key', 'here!');
+    i18nInstance.addResource('en', 'translation', 'deeply.nested_a.key', 'here_a!');
+    i18nInstance.addResource('en', 'translation', 'deeply.nested_b.key', 'here_b!');
 
-    it('should apply keyPrefix', () => {
-      const { result } = renderHook(() =>
-        useTranslation('translation', { i18n: i18nInstance, keyPrefix: 'deeply.nested' }),
+    it('should apply keyPrefix and reset it once changed', () => {
+      let keyPrefix = 'deeply.nested_a';
+      const { result, rerender } = renderHook(() =>
+        useTranslation('translation', { i18n: i18nInstance, keyPrefix }),
       );
-      const { t } = result.current;
-      expect(t('key')).toBe('here!');
-      expect(t.keyPrefix).toBe('deeply.nested');
+      const { t: t1 } = result.current;
+      expect(t1('key')).toBe('here_a!');
+      expect(t1.keyPrefix).toBe('deeply.nested_a');
+
+      keyPrefix = 'deeply.nested_b';
+      rerender();
+
+      const { t: t2 } = result.current;
+      expect(t2('key')).toBe('here_b!');
+      expect(t2.keyPrefix).toBe('deeply.nested_b');
     });
   });