fix: add error handling to examples

WE2-1179

Signed-off-by: Sven Mitt <svenzik@users.noreply.github.com>

Author: svenzik

README.md

@@ -745,7 +745,54 @@ Errors returned by the library have a `code` property which contains the program
 To avoid typos, you can use the `ErrorCode` enum to refer to the codes.
 
 **Example**
+The `examples` directory contains fully working applications demonstrating authentication and digital signing. 
+
+There is two approaches to handle errors:
 ```ts
+// by Error instance
+const onLogin = async () => {
+  setLoading(true)
+  setAlert(undefined)
+
+  try {
+    await loginWithIdCard()
+    navigate('/sign')
+  } catch (error) {
+    if (error instanceof UserTimeoutError) {
+      setAlert("ID-card authentication timed out, please try again");
+    } else if (error instanceof UserCancelledError) {
+      setAlert("ID-card authentication was cancelled by the user");
+    } else if (error instanceof ExtensionUnavailableError) {
+      setAlert("Web eID browser extension is not available, please install it or enable it to continue");
+    } else if (error instanceof NativeUnavailableError) {
+      setAlert("Web eID native application is not installed, please install it to continue");
+    } else if (error instanceof VersionInvalidError) {
+      setAlert("Web eID native application did not provide a valid version string during handshake, please report a bug");
+    } else if (error instanceof VersionMismatchError) {
+      if (error.requiresUpdate?.extension) {
+        setAlert("Please update the Web eID browser extension");
+      } else if (error.requiresUpdate?.nativeApp) {
+        setAlert("Please update the Web eID native application");
+      } else {
+        setAlert("Please update the Web eID native application and browser extension");
+      }
+    } else if (error instanceof ContextInsecureError) {
+      setAlert("Web eID requires a secure HTTPS connection. Please contact the website administrator");
+    } else if (error instanceof NativeFatalError) {
+      setAlert("Please try again. If the problem persists, contact support");
+    } else if (error instanceof UnknownError) {
+      setAlert(`An unknown error occurred. Please try again and contact support if the problem persists! ${error.message} (${error.code})`);
+    } else {
+      const errorMessage = error instanceof Error ? error.message : String(error);
+      const errorCode = isKnownWebEidError(error) ? ` (${(error as any).code})` : "";
+      setAlert(`An unknown error occurred. Please try again and contact support if the problem persists! ${errorMessage}${errorCode}`);
+    }
+
+  } finally {
+    setLoading(false)
+  }
+}
+// Or by Error.code
 try {
   const {
       certificate,
@@ -760,7 +807,6 @@ try {
       showError("Signing certificate retrieval timed out, please try again!");
       break;
     }
-
     // other cases
 
     default: {

examples/web-eid-angular-example/angular.json

@@ -56,6 +56,9 @@
           "defaultConfiguration": "production"
         },
         "serve": {
+          "options": {
+            "allowedHosts": ["localhost"]
+          },
           "builder": "@angular/build:dev-server",
           "configurations": {
             "production": {