Fix issue which was defaulting TFunctionResult for t function (i18nex…

…t#1217)
pedrodurek · Dec 9, 2020 · 24b1ee4 · 24b1ee4
1 parent fca2b73
commit 24b1ee4
Showing 1 changed file with 18 additions and 16 deletions.
diff --git a/src/ts4.1/index.d.ts b/src/ts4.1/index.d.ts
@@ -84,30 +84,32 @@ export type TFuncKey<N, T = Resources> = N extends (keyof T)[]
   ? Normalize<T[N]>
   : string;
 
-export type TFuncReturn<N, P, T = Resources> = N extends (keyof T)[]
-  ? NormalizeMultiReturn<T, P>
+export type TFuncReturn<N, TKeys, TDefaultResult, T = Resources> = [keyof Resources] extends [never]
+  ? TDefaultResult
+  : N extends (keyof T)[]
+  ? NormalizeMultiReturn<T, TKeys>
   : N extends keyof T
-  ? NormalizeReturn<T[N], P>
-  : TFunctionResult;
+  ? NormalizeReturn<T[N], TKeys>
+  : string;
 
 export interface TFunction<N extends Namespace = DefaultNamespace> {
   <
-    K extends TFuncKey<N> | TemplateStringsArray,
-    R extends TFuncReturn<N, K>,
-    I extends object = StringMap
+    TKeys extends TFuncKey<N> | TemplateStringsArray,
+    TDefaultResult extends TFunctionResult = string,
+    TInterpolationMap extends object = StringMap
   >(
-    key: K | K[],
-    options?: TOptions<I> | string,
-  ): R;
+    key: TKeys | TKeys[],
+    options?: TOptions<TInterpolationMap> | string,
+  ): TFuncReturn<N, TKeys, TDefaultResult>;
   <
-    K extends TFuncKey<N> | TemplateStringsArray,
-    R extends TFuncReturn<N, K>,
-    I extends object = StringMap
+    TKeys extends TFuncKey<N> | TemplateStringsArray,
+    TDefaultResult extends TFunctionResult = string,
+    TInterpolationMap extends object = StringMap
   >(
-    key: K | K[],
+    key: TKeys | TKeys[],
     defaultValue?: string,
-    options?: TOptions<I> | string,
-  ): R;
+    options?: TOptions<TInterpolationMap> | string,
+  ): TFuncReturn<N, TKeys, TDefaultResult>;
 }
 
 export interface TransProps<