flow like the river

BACK_BACK/node_modules/graphql/validation/rules/UniqueInputFieldNamesRule.mjs

@@ -0,0 +1,32 @@
+import { GraphQLError } from "../../error/GraphQLError.mjs";
+
+/**
+ * Unique input field names
+ *
+ * A GraphQL input object value is only valid if all supplied fields are
+ * uniquely named.
+ */
+export function UniqueInputFieldNamesRule(context) {
+  var knownNameStack = [];
+  var knownNames = Object.create(null);
+  return {
+    ObjectValue: {
+      enter: function enter() {
+        knownNameStack.push(knownNames);
+        knownNames = Object.create(null);
+      },
+      leave: function leave() {
+        knownNames = knownNameStack.pop();
+      }
+    },
+    ObjectField: function ObjectField(node) {
+      var fieldName = node.name.value;
+
+      if (knownNames[fieldName]) {
+        context.reportError(new GraphQLError("There can be only one input field named \"".concat(fieldName, "\"."), [knownNames[fieldName], node.name]));
+      } else {
+        knownNames[fieldName] = node.name;
+      }
+    }
+  };
+}