text: "use strict";
  
  Object.defineProperty(exports, "__esModule", {
    value: true
  });
  exports.UniqueVariableNames = UniqueVariableNames;
  
  var _GraphQLError = require("../../error/GraphQLError");
  
  /**
   * Unique variable names
   *
   * A GraphQL operation is only valid if all its variables are uniquely named.
   */
  function UniqueVariableNames(context) {
    var knownVariableNames = Object.create(null);
    return {
      OperationDefinition: function OperationDefinition() {
        knownVariableNames = Object.create(null);
      },
      VariableDefinition: function VariableDefinition(node) {
        var variableName = node.variable.name.value;
  
        if (knownVariableNames[variableName]) {
          context.reportError(new _GraphQLError.GraphQLError("There can be only one variable named \"$".concat(variableName, "\"."), [knownVariableNames[variableName], node.variable.name]));
        } else {
          knownVariableNames[variableName] = node.variable.name;
        }
      }
    };
  }
  