1 files changed, 34 insertions, 6 deletions
diff --git a/packages/taler-wallet-webextension/src/mui/handlers.ts b/packages/taler-wallet-webextension/src/mui/handlers.ts
index 655fceef9..61786742f 100644
--- a/packages/taler-wallet-webextension/src/mui/handlers.ts
+++ b/packages/taler-wallet-webextension/src/mui/handlers.ts
@@ -14,23 +14,51 @@
  GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
  */
 import { AmountJson } from "@gnu-taler/taler-util";
-import { TalerError } from "@gnu-taler/taler-wallet-core";
 
 export interface TextFieldHandler {
-  onInput?: (value: string) => Promise<void>;
+  onInput?: SafeHandler<string>;
   value: string;
   error?: string;
 }
 
 export interface AmountFieldHandler {
-  onInput?: (value: AmountJson) => Promise<void>;
+  onInput?: SafeHandler<AmountJson>;
   value: AmountJson;
   error?: string;
 }
 
+declare const __safe_handler: unique symbol;
+export type SafeHandler<T> = {
+  <Req extends T>(req: Req): Promise<void>;
+  (): Promise<void>;
+  [__safe_handler]: true;
+};
+
+export function withSafe<T>(
+  handler: (p: T) => Promise<void>,
+  onError: (e: Error) => void,
+): SafeHandler<T> {
+  const sh = async function (p: T): Promise<void> {
+    try {
+      await handler(p);
+    } catch (e) {
+      if (e instanceof Error) {
+        onError(e);
+      } else {
+        onError(new Error(String(e)));
+      }
+    }
+  };
+  return sh as SafeHandler<T>;
+}
+
+export const nullFunction = async function (): Promise<void> {
+  //do nothing
+} as SafeHandler<void>;
+
 export interface ButtonHandler {
-  onClick?: () => Promise<void>;
-  error?: TalerError;
+  onClick?: SafeHandler<void>;
+  // error?: TalerError;
 }
 
 export interface ToggleHandler {
@@ -39,7 +67,7 @@ export interface ToggleHandler {
 }
 
 export interface SelectFieldHandler {
-  onChange?: (value: string) => Promise<void>;
+  onChange?: SafeHandler<string>;
   error?: string;
   value: string;
   isDirty?: boolean;