rpc: document errors.Is(..., ErrNotificationsUnsupported) better

ethereum · Jun 14, 2023 · 406506c · 406506c
1 parent 7146379
commit 406506c
Showing 1 changed file with 9 additions and 1 deletion.
diff --git a/rpc/subscription.go b/rpc/subscription.go
@@ -32,7 +32,15 @@ import (
 )
 
 var (
-	// ErrNotificationsUnsupported is returned when the connection doesn't support notifications
+	// ErrNotificationsUnsupported is returned by the client when the connection doesn't
+	// support notifications. You can use this error value to check for subscription
+	// support like this:
+	//
+	//	sub, err := client.EthSubscribe(ctx, channel, "newHeads", true)
+	//	if errors.Is(err, rpc.ErrNotificationsUnsupported) {
+	//		// Server does not support subscriptions, fall back to polling.
+	//	}
+	//
 	ErrNotificationsUnsupported = notificationsUnsupportedError{}
 
 	// ErrSubscriptionNotFound is returned when the notification for the given id is not found