fix(useErrorBoundary): state type narrow (#161)

Author: manudeli

src/useErrorBoundary.ts

@@ -2,20 +2,21 @@ import { useContext, useMemo, useState } from "react";
 import { assertErrorBoundaryContext } from "./assertErrorBoundaryContext";
 import { ErrorBoundaryContext } from "./ErrorBoundaryContext";
 
-export type UseErrorBoundaryApi<Error> = {
+type UseErrorBoundaryState<TError> =
+  | { error: TError; hasError: true }
+  | { error: null; hasError: false };
+
+export type UseErrorBoundaryApi<TError> = {
   resetBoundary: () => void;
-  showBoundary: (error: Error) => void;
+  showBoundary: (error: TError) => void;
 };
 
-export function useErrorBoundary<Error = any>(): UseErrorBoundaryApi<Error> {
+export function useErrorBoundary<TError = any>(): UseErrorBoundaryApi<TError> {
   const context = useContext(ErrorBoundaryContext);
 
   assertErrorBoundaryContext(context);
 
-  const [state, setState] = useState<{
-    error: Error | null;
-    hasError: boolean;
-  }>({
+  const [state, setState] = useState<UseErrorBoundaryState<TError>>({
     error: null,
     hasError: false,
   });
@@ -26,7 +27,7 @@ export function useErrorBoundary<Error = any>(): UseErrorBoundaryApi<Error> {
         context?.resetErrorBoundary();
         setState({ error: null, hasError: false });
       },
-      showBoundary: (error: Error) =>
+      showBoundary: (error: TError) =>
         setState({
           error,
           hasError: true,