flow like the river

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

@@ -0,0 +1,34 @@
+import { GraphQLError } from "../../error/GraphQLError.mjs";
+
+/**
+ * No undefined variables
+ *
+ * A GraphQL operation is only valid if all variables encountered, both directly
+ * and via fragment spreads, are defined by that operation.
+ */
+export function NoUndefinedVariablesRule(context) {
+  var variableNameDefined = Object.create(null);
+  return {
+    OperationDefinition: {
+      enter: function enter() {
+        variableNameDefined = Object.create(null);
+      },
+      leave: function leave(operation) {
+        var usages = context.getRecursiveVariableUsages(operation);
+
+        for (var _i2 = 0; _i2 < usages.length; _i2++) {
+          var _ref2 = usages[_i2];
+          var node = _ref2.node;
+          var varName = node.name.value;
+
+          if (variableNameDefined[varName] !== true) {
+            context.reportError(new GraphQLError(operation.name ? "Variable \"$".concat(varName, "\" is not defined by operation \"").concat(operation.name.value, "\".") : "Variable \"$".concat(varName, "\" is not defined."), [node, operation]));
+          }
+        }
+      }
+    },
+    VariableDefinition: function VariableDefinition(node) {
+      variableNameDefined[node.variable.name.value] = true;
+    }
+  };
+}