fix #1899

Author: cellog

index.d.ts

@@ -47,7 +47,7 @@ export interface IcuTransContentDeclaration {
  * Props for IcuTransWithoutContext component (no React context)
  */
 export type IcuTransWithoutContextProps<
-  Key extends ParseKeys<Ns, TOpt, KPrefix> = string,
+  Key extends ParseKeys<Ns, TOpt, KPrefix>,
   Ns extends Namespace = _DefaultNamespace,
   KPrefix = undefined,
   TContext extends string | undefined = undefined,
@@ -73,7 +73,7 @@ export type IcuTransWithoutContextProps<
  * Props for IcuTrans component (with React context support)
  */
 export type IcuTransProps<
-  Key extends ParseKeys<Ns, TOpt, KPrefix> = string,
+  Key extends ParseKeys<Ns, TOpt, KPrefix>,
   Ns extends Namespace = _DefaultNamespace,
   KPrefix = undefined,
   TContext extends string | undefined = undefined,
@@ -96,7 +96,7 @@ export type IcuTransProps<
  */
 export interface IcuTransComponent {
   <
-    Key extends ParseKeys<Ns, TOpt, KPrefix> = string,
+    Key extends ParseKeys<Ns, TOpt, KPrefix>,
     Ns extends Namespace = _DefaultNamespace,
     KPrefix = undefined,
     TContext extends string | undefined = undefined,
@@ -123,7 +123,7 @@ export interface IcuTransComponent {
  */
 export interface IcuTransWithoutContextComponent {
   <
-    Key extends ParseKeys<Ns, TOpt, KPrefix> = string,
+    Key extends ParseKeys<Ns, TOpt, KPrefix>,
     Ns extends Namespace = _DefaultNamespace,
     KPrefix = undefined,
     TContext extends string | undefined = undefined,

test/typescript/reproduce-1899/IcuTrans.test.tsx

@@ -0,0 +1,15 @@
+import { describe, it, expectTypeOf } from 'vitest';
+import { IcuTrans } from '../../..';
+
+describe('<IcuTrans /> with bug report config', () => {
+  it('standard usage should work', () => {
+    // This is the basic test case from issue #1899
+    // The bug is that when resources are defined, the default type parameter
+    // `= string` becomes invalid because ParseKeys<...> returns specific keys
+    expectTypeOf(IcuTrans).toBeCallableWith({
+      i18nKey: 'foo',
+      defaultTranslation: 'foo',
+      content: [],
+    });
+  });
+});

test/typescript/reproduce-1899/i18next.d.ts

@@ -0,0 +1,11 @@
+import 'i18next';
+
+declare module 'i18next' {
+  interface CustomTypeOptions {
+    defaultNS: 'app';
+    keySeparator: '.';
+    resources: {
+      app: { foo: string; bar: string };
+    };
+  }
+}

test/typescript/reproduce-1899/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "extends": "../../../tsconfig.json",
+  "include": ["./**/*"],
+  "exclude": [],
+  "compilerOptions": {
+    "skipLibCheck": false
+  }
+}