graphql/validation/rules/UniqueEnumValueNamesRule.mjs

import { GraphQLError } from "../../error/GraphQLError.mjs";
import { isEnumType } from "../../type/definition.mjs";

/**
 * Unique enum value names
 *
 * A GraphQL enum type is only valid if all its values are uniquely named.
 */
export function UniqueEnumValueNamesRule(context) {
  var schema = context.getSchema();
  var existingTypeMap = schema ? schema.getTypeMap() : Object.create(null);
  var knownValueNames = Object.create(null);
  return {
    EnumTypeDefinition: checkValueUniqueness,
    EnumTypeExtension: checkValueUniqueness
  };

  function checkValueUniqueness(node) {
    var _node$values;

    var typeName = node.name.value;

    if (!knownValueNames[typeName]) {
      knownValueNames[typeName] = Object.create(null);
    } // istanbul ignore next (See: 'https://github.com/graphql/graphql-js/issues/2203')


    var valueNodes = (_node$values = node.values) !== null && _node$values !== void 0 ? _node$values : [];
    var valueNames = knownValueNames[typeName];

    for (var _i2 = 0; _i2 < valueNodes.length; _i2++) {
      var valueDef = valueNodes[_i2];
      var valueName = valueDef.name.value;
      var existingType = existingTypeMap[typeName];

      if (isEnumType(existingType) && existingType.getValue(valueName)) {
        context.reportError(new GraphQLError("Enum value \"".concat(typeName, ".").concat(valueName, "\" already exists in the schema. It cannot also be defined in this type extension."), valueDef.name));
      } else if (valueNames[valueName]) {
        context.reportError(new GraphQLError("Enum value \"".concat(typeName, ".").concat(valueName, "\" can only be defined once."), [valueNames[valueName], valueDef.name]));
      } else {
        valueNames[valueName] = valueDef.name;
      }
    }

    return false;
  }
}