blips/es/utils/rules.js

State management for the GraphQL heads

import { GraphQLError } from 'graphql';

import { isFragmentDefinition } from './isFragmentDefinition';
import { getOperationName } from './getOperationName';

export function singleFieldOnlyMessage(name) {
  return (name ? 'Subscription "' + name + '" ' : 'Anonymous Subscription ') + 'must select only one top level field.';
}

export function anonOperationNotAloneMessage() {
  return 'This anonymous operation must be the only defined operation.';
}

export function duplicateFragmentNameMessage(fragName) {
  return 'There can be only one fragment named "' + fragName + '".';
}

/**
 * Subscriptions must only include one field.
 *
 * A GraphQL subscription is valid only if it contains a single root field.
 */
export function singleFieldSubscriptions(node) {
  if (node.operation === 'subscription') {
    if (node.selectionSet.selections.length !== 1) {
      return new GraphQLError(singleFieldOnlyMessage(node.name && node.name.value), node.selectionSet.selections.slice(1));
    }
  }
}

/**
 * Lone anonymous operation
 *
 * A GraphQL document is only valid if when it contains an anonymous operation
 * (the query short-hand) that it contains only that one operation definition.
 */
/**
 * 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.
 *
 *
 */

export function loneAnonymousOperation(node, operationCount) {
  if (!node.name && operationCount > 1) {
    return new GraphQLError(anonOperationNotAloneMessage(), [node]);
  }
}

/**
 * Unique fragment names
 *
 * A GraphQL document is only valid if all defined fragments have unique names.
 */
export function uniqueFragmentNames(node, knownFragmentNames) {
  if (!isFragmentDefinition(node)) return;

  var fragmentName = getOperationName(node);

  if (knownFragmentNames[fragmentName]) {
    return new GraphQLError(duplicateFragmentNameMessage(fragmentName), [knownFragmentNames[fragmentName], node.name]);
  } else {
    knownFragmentNames[fragmentName] = node.name;
  }
}