Initial commit

server/node_modules/graphql/validation/rules/SingleFieldSubscriptions.mjs

@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ *  strict
+ */
+import { GraphQLError } from '../../error/GraphQLError';
+export function singleFieldOnlyMessage(name) {
+  return (name ? "Subscription \"".concat(name, "\" ") : 'Anonymous Subscription ') + 'must select only one top level field.';
+}
+/**
+ * Subscriptions must only include one field.
+ *
+ * A GraphQL subscription is valid only if it contains a single root field.
+ */
+
+export function SingleFieldSubscriptions(context) {
+  return {
+    OperationDefinition: function OperationDefinition(node) {
+      if (node.operation === 'subscription') {
+        if (node.selectionSet.selections.length !== 1) {
+          context.reportError(new GraphQLError(singleFieldOnlyMessage(node.name && node.name.value), node.selectionSet.selections.slice(1)));
+        }
+      }
+    }
+  };
+}