try to fix Trans handling with alwaysFormat set to true #1801

CHANGELOG.md

@@ -1,3 +1,7 @@
+### 15.0.2
+
+- try to fix Trans handling with alwaysFormat set to true [1801](https://github.com/i18next/react-i18next/issues/1801)
+
 ### 15.0.1
 
 - revert arrow function in class property to address [this](https://github.com/i18next/react-i18next/commit/46e8ea5ff69325b73087811a2ce6a2b1faffa971#r145061161)

react-i18next.js

@@ -452,7 +452,7 @@
 	      ...i18n.options.interpolation.defaultVariables
 	    };
 	  }
-	  const interpolationOverride = values || count !== undefined || !children ? tOptions.interpolation : {
+	  const interpolationOverride = values || count !== undefined && !i18n.options?.interpolation?.alwaysFormat || !children ? tOptions.interpolation : {
 	    interpolation: {
 	      ...tOptions.interpolation,
 	      prefix: '#$?',

src/TransWithoutContext.js

@@ -344,7 +344,9 @@ export function Trans({
         : { ...i18n.options.interpolation.defaultVariables };
   }
   const interpolationOverride =
-    values || count !== undefined || !children // if !children gets problems in future, undo that fix: https://github.com/i18next/react-i18next/issues/1729 by removing !children from this condition
+    values ||
+    (count !== undefined && !i18n.options?.interpolation?.alwaysFormat) || // https://github.com/i18next/react-i18next/issues/1719 + https://github.com/i18next/react-i18next/issues/1801
+    !children // if !children gets problems in future, undo that fix: https://github.com/i18next/react-i18next/issues/1729 by removing !children from this condition
       ? tOptions.interpolation
       : { interpolation: { ...tOptions.interpolation, prefix: '#$?', suffix: '?$#' } };
   const combinedTOpts = {

test/trans.render.spec.jsx

@@ -1,4 +1,4 @@
-import { describe, it, expect, beforeAll, afterAll, afterEach } from 'vitest';
+import { describe, it, expect, beforeAll, afterAll, beforeEach, afterEach } from 'vitest';
 import React from 'react';
 import { render, cleanup } from '@testing-library/react';
 import i18n from './i18n';
@@ -891,6 +891,43 @@ describe('trans with formatting', () => {
   });
 });
 
+describe('trans with formatting with alwaysFormat', () => {
+  let newI18n;
+
+  beforeEach(() => {
+    newI18n = i18n.createInstance();
+    newI18n.init({
+      interpolation: {
+        alwaysFormat: true,
+        escapeValue: false,
+        format: (value) => `(formatted ${value})`,
+      },
+    });
+  });
+
+  function TestComponent({ parent }) {
+    const name = 'Fritz';
+    return (
+      <Trans parent={parent} i18n={newI18n} count={3}>
+        number: {'{{count, INTEGER}}'}
+        <br />
+        name: {{ name }}
+      </Trans>
+    );
+  }
+
+  it('should render correct content', () => {
+    const { container } = render(<TestComponent />);
+    expect(container).toMatchInlineSnapshot(`
+      <div>
+        number: (formatted 3)
+        <br />
+        name: (formatted Fritz)
+      </div>
+    `);
+  });
+});
+
 describe('trans with undefined context property', () => {
   function TestComponent({ parent }) {
     return (