graphql/lib/validator/rules/PossibleFragmentSpreads.js

A Query Language and Runtime which can target any service.

/* @flow */
/**
 *  Copyright (c) 2015, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree. An additional grant
 *  of patent rights can be found in the PATENTS file in the same directory.
 */

'use strict';

var _Object$defineProperty = require('babel-runtime/core-js/object/define-property')['default'];

var _interopRequireDefault = require('babel-runtime/helpers/interop-require-default')['default'];

_Object$defineProperty(exports, '__esModule', {
  value: true
});

exports['default'] = PossibleFragmentSpreads;

var _error = require('../../error');

var _typeDefinition = require('../../type/definition');

var _utilsKeyMap = require('../../utils/keyMap');

var _utilsKeyMap2 = _interopRequireDefault(_utilsKeyMap);

var _errors = require('../errors');

/**
 * Possible fragment spread
 *
 * A fragment spread is only valid if the type condition could ever possibly
 * be true: if there is a non-empty intersection of the possible parent types,
 * and possible types which pass the type condition.
 */

function PossibleFragmentSpreads(context) {
  return {
    InlineFragment: function InlineFragment(node) {
      var fragType = (0, _typeDefinition.getUnmodifiedType)(context.getType());
      var parentType = context.getParentType();
      if (fragType && parentType && !doTypesOverlap(fragType, parentType)) {
        return new _error.GraphQLError((0, _errors.typeIncompatibleAnonSpreadMessage)(parentType, fragType), [node]);
      }
    },
    FragmentSpread: function FragmentSpread(node) {
      var fragName = node.name.value;
      var fragType = (0, _typeDefinition.getUnmodifiedType)(getFragmentType(context, fragName));
      var parentType = context.getParentType();
      if (fragType && parentType && !doTypesOverlap(fragType, parentType)) {
        return new _error.GraphQLError((0, _errors.typeIncompatibleSpreadMessage)(fragName, parentType, fragType), [node]);
      }
    }
  };
}

function getFragmentType(context, name) {
  var frag = context.getFragment(name);
  return frag && context.getSchema().getType(frag.typeCondition.value);
}

function doTypesOverlap(t1, t2) {
  if (t1 === t2) {
    return true;
  }
  if (t1 instanceof _typeDefinition.GraphQLObjectType) {
    if (t2 instanceof _typeDefinition.GraphQLObjectType) {
      return false;
    }
    return t2.getPossibleTypes().indexOf(t1) !== -1;
  }
  if (t1 instanceof _typeDefinition.GraphQLInterfaceType || t1 instanceof _typeDefinition.GraphQLUnionType) {
    if (t2 instanceof _typeDefinition.GraphQLObjectType) {
      return t1.getPossibleTypes().indexOf(t2) !== -1;
    }
    var t1TypeNames = (0, _utilsKeyMap2['default'])(t1.getPossibleTypes(), function (type) {
      return type.name;
    });
    return t2.getPossibleTypes().some(function (type) {
      return t1TypeNames[type.name];
    });
  }
}
module.exports = exports['default'];