'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.GraphQLNonNull = exports.GraphQLList = exports.GraphQLInputObjectType = exports.GraphQLEnumType = exports.GraphQLUnionType = exports.GraphQLInterfaceType = exports.GraphQLObjectType = exports.GraphQLScalarType = undefined;

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

exports.isType = isType;
exports.assertType = assertType;
exports.isInputType = isInputType;
exports.assertInputType = assertInputType;
exports.isOutputType = isOutputType;
exports.assertOutputType = assertOutputType;
exports.isLeafType = isLeafType;
exports.assertLeafType = assertLeafType;
exports.isCompositeType = isCompositeType;
exports.assertCompositeType = assertCompositeType;
exports.isAbstractType = isAbstractType;
exports.assertAbstractType = assertAbstractType;
exports.getNullableType = getNullableType;
exports.isNamedType = isNamedType;
exports.assertNamedType = assertNamedType;
exports.getNamedType = getNamedType;

var _invariant = require('../jsutils/invariant');

var _invariant2 = _interopRequireDefault(_invariant);

var _isNullish = require('../jsutils/isNullish');

var _isNullish2 = _interopRequireDefault(_isNullish);

var _kinds = require('../language/kinds');

var _assertValidName = require('../utilities/assertValidName');

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
/**
 *  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.
 */

// Predicates & Assertions

/**
 * These are all of the possible kinds of types.
 */
function isType(type) {
  return type instanceof GraphQLScalarType || type instanceof GraphQLObjectType || type instanceof GraphQLInterfaceType || type instanceof GraphQLUnionType || type instanceof GraphQLEnumType || type instanceof GraphQLInputObjectType || type instanceof GraphQLList || type instanceof GraphQLNonNull;
}

function assertType(type) {
  (0, _invariant2.default)(isType(type), 'Expected ' + String(type) + ' to be a GraphQL type.');
  return type;
}

/**
 * These types may be used as input types for arguments and directives.
 */
function isInputType(type) {
  var namedType = getNamedType(type);
  return namedType instanceof GraphQLScalarType || namedType instanceof GraphQLEnumType || namedType instanceof GraphQLInputObjectType;
}

function assertInputType(type) {
  (0, _invariant2.default)(isInputType(type), 'Expected ' + String(type) + ' to be a GraphQL input type.');
  return type;
}

/**
 * These types may be used as output types as the result of fields.
 */
function isOutputType(type) {
  var namedType = getNamedType(type);
  return namedType instanceof GraphQLScalarType || namedType instanceof GraphQLObjectType || namedType instanceof GraphQLInterfaceType || namedType instanceof GraphQLUnionType || namedType instanceof GraphQLEnumType;
}

function assertOutputType(type) {
  (0, _invariant2.default)(isOutputType(type), 'Expected ' + String(type) + ' to be a GraphQL output type.');
  return type;
}

/**
 * These types may describe types which may be leaf values.
 */
function isLeafType(type) {
  var namedType = getNamedType(type);
  return namedType instanceof GraphQLScalarType || namedType instanceof GraphQLEnumType;
}

function assertLeafType(type) {
  (0, _invariant2.default)(isLeafType(type), 'Expected ' + String(type) + ' to be a GraphQL leaf type.');
  return type;
}

/**
 * These types may describe the parent context of a selection set.
 */
function isCompositeType(type) {
  return type instanceof GraphQLObjectType || type instanceof GraphQLInterfaceType || type instanceof GraphQLUnionType;
}

function assertCompositeType(type) {
  (0, _invariant2.default)(isCompositeType(type), 'Expected ' + String(type) + ' to be a GraphQL composite type.');
  return type;
}

/**
 * These types may describe the parent context of a selection set.
 */
function isAbstractType(type) {
  return type instanceof GraphQLInterfaceType || type instanceof GraphQLUnionType;
}

function assertAbstractType(type) {
  (0, _invariant2.default)(isAbstractType(type), 'Expected ' + String(type) + ' to be a GraphQL abstract type.');
  return type;
}

/**
 * These types can all accept null as a value.
 */
function getNullableType(type) {
  return type instanceof GraphQLNonNull ? type.ofType : type;
}

/**
 * These named types do not include modifiers like List or NonNull.
 */
function isNamedType(type) {
  return type instanceof GraphQLScalarType || type instanceof GraphQLObjectType || type instanceof GraphQLInterfaceType || type instanceof GraphQLUnionType || type instanceof GraphQLEnumType || type instanceof GraphQLInputObjectType;
}

function assertNamedType(type) {
  (0, _invariant2.default)(isNamedType(type), 'Expected ' + String(type) + ' to be a GraphQL named type.');
  return type;
}

function getNamedType(type) {
  var unmodifiedType = type;
  while (unmodifiedType instanceof GraphQLList || unmodifiedType instanceof GraphQLNonNull) {
    unmodifiedType = unmodifiedType.ofType;
  }
  return unmodifiedType;
}

/**
 * Used while defining GraphQL types to allow for circular references in
 * otherwise immutable type definitions.
 */


function resolveThunk(thunk) {
  return typeof thunk === 'function' ? thunk() : thunk;
}

/**
 * Scalar Type Definition
 *
 * The leaf values of any request and input values to arguments are
 * Scalars (or Enums) and are defined with a name and a series of functions
 * used to parse input from ast or variables and to ensure validity.
 *
 * Example:
 *
 *     const OddType = new GraphQLScalarType({
 *       name: 'Odd',
 *       serialize(value) {
 *         return value % 2 === 1 ? value : null;
 *       }
 *     });
 *
 */

var GraphQLScalarType = exports.GraphQLScalarType = function () {
  function GraphQLScalarType(config) {
    _classCallCheck(this, GraphQLScalarType);

    (0, _assertValidName.assertValidName)(config.name);
    this.name = config.name;
    this.description = config.description;
    (0, _invariant2.default)(typeof config.serialize === 'function', this.name + ' must provide "serialize" function. If this custom Scalar ' + 'is also used as an input type, ensure "parseValue" and "parseLiteral" ' + 'functions are also provided.');
    if (config.parseValue || config.parseLiteral) {
      (0, _invariant2.default)(typeof config.parseValue === 'function' && typeof config.parseLiteral === 'function', this.name + ' must provide both "parseValue" and "parseLiteral" ' + 'functions.');
    }
    this._scalarConfig = config;
  }

  // Serializes an internal value to include in a response.


  GraphQLScalarType.prototype.serialize = function serialize(value) {
    var serializer = this._scalarConfig.serialize;
    return serializer(value);
  };

  // Parses an externally provided value to use as an input.


  GraphQLScalarType.prototype.parseValue = function parseValue(value) {
    var parser = this._scalarConfig.parseValue;
    return parser ? parser(value) : null;
  };

  // Parses an externally provided literal value to use as an input.


  GraphQLScalarType.prototype.parseLiteral = function parseLiteral(valueNode) {
    var parser = this._scalarConfig.parseLiteral;
    return parser ? parser(valueNode) : null;
  };

  GraphQLScalarType.prototype.toString = function toString() {
    return this.name;
  };

  return GraphQLScalarType;
}();

// Also provide toJSON and inspect aliases for toString.


GraphQLScalarType.prototype.toJSON = GraphQLScalarType.prototype.inspect = GraphQLScalarType.prototype.toString;

/**
 * Object Type Definition
 *
 * Almost all of the GraphQL types you define will be object types. Object types
 * have a name, but most importantly describe their fields.
 *
 * Example:
 *
 *     const AddressType = new GraphQLObjectType({
 *       name: 'Address',
 *       fields: {
 *         street: { type: GraphQLString },
 *         number: { type: GraphQLInt },
 *         formatted: {
 *           type: GraphQLString,
 *           resolve(obj) {
 *             return obj.number + ' ' + obj.street
 *           }
 *         }
 *       }
 *     });
 *
 * When two types need to refer to each other, or a type needs to refer to
 * itself in a field, you can use a function expression (aka a closure or a
 * thunk) to supply the fields lazily.
 *
 * Example:
 *
 *     const PersonType = new GraphQLObjectType({
 *       name: 'Person',
 *       fields: () => ({
 *         name: { type: GraphQLString },
 *         bestFriend: { type: PersonType },
 *       })
 *     });
 *
 */
var GraphQLObjectType = exports.GraphQLObjectType = function () {
  function GraphQLObjectType(config) {
    _classCallCheck(this, GraphQLObjectType);

    (0, _assertValidName.assertValidName)(config.name, config.isIntrospection);
    this.name = config.name;
    this.description = config.description;
    if (config.isTypeOf) {
      (0, _invariant2.default)(typeof config.isTypeOf === 'function', this.name + ' must provide "isTypeOf" as a function.');
    }
    this.isTypeOf = config.isTypeOf;
    this._typeConfig = config;
  }

  GraphQLObjectType.prototype.getFields = function getFields() {
    return this._fields || (this._fields = defineFieldMap(this, this._typeConfig.fields));
  };

  GraphQLObjectType.prototype.getInterfaces = function getInterfaces() {
    return this._interfaces || (this._interfaces = defineInterfaces(this, this._typeConfig.interfaces));
  };

  GraphQLObjectType.prototype.toString = function toString() {
    return this.name;
  };

  return GraphQLObjectType;
}();

// Also provide toJSON and inspect aliases for toString.


GraphQLObjectType.prototype.toJSON = GraphQLObjectType.prototype.inspect = GraphQLObjectType.prototype.toString;

function defineInterfaces(type, interfacesThunk) {
  var interfaces = resolveThunk(interfacesThunk);
  if (!interfaces) {
    return [];
  }
  (0, _invariant2.default)(Array.isArray(interfaces), type.name + ' interfaces must be an Array or a function which returns ' + 'an Array.');
  interfaces.forEach(function (iface) {
    (0, _invariant2.default)(iface instanceof GraphQLInterfaceType, type.name + ' may only implement Interface types, it cannot ' + ('implement: ' + String(iface) + '.'));
    if (typeof iface.resolveType !== 'function') {
      (0, _invariant2.default)(typeof type.isTypeOf === 'function', 'Interface Type ' + iface.name + ' does not provide a "resolveType" ' + ('function and implementing Type ' + type.name + ' does not provide a ') + '"isTypeOf" function. There is no way to resolve this implementing ' + 'type during execution.');
    }
  });
  return interfaces;
}

function defineFieldMap(type, fieldsThunk) {
  var fieldMap = resolveThunk(fieldsThunk);
  (0, _invariant2.default)(isPlainObj(fieldMap), type.name + ' fields must be an object with field names as keys or a ' + 'function which returns such an object.');

  var fieldNames = Object.keys(fieldMap);
  (0, _invariant2.default)(fieldNames.length > 0, type.name + ' fields must be an object with field names as keys or a ' + 'function which returns such an object.');

  var resultFieldMap = {};
  fieldNames.forEach(function (fieldName) {
    (0, _assertValidName.assertValidName)(fieldName);
    var fieldConfig = fieldMap[fieldName];
    (0, _invariant2.default)(!fieldConfig.hasOwnProperty('isDeprecated'), type.name + '.' + fieldName + ' should provide "deprecationReason" instead ' + 'of "isDeprecated".');
    var field = _extends({}, fieldConfig, {
      isDeprecated: Boolean(fieldConfig.deprecationReason),
      name: fieldName
    });
    (0, _invariant2.default)(isOutputType(field.type), type.name + '.' + fieldName + ' field type must be Output Type but ' + ('got: ' + String(field.type) + '.'));
    (0, _invariant2.default)(isValidResolver(field.resolve), type.name + '.' + fieldName + ' field resolver must be a function if ' + ('provided, but got: ' + String(field.resolve) + '.'));
    var argsConfig = fieldConfig.args;
    if (!argsConfig) {
      field.args = [];
    } else {
      (0, _invariant2.default)(isPlainObj(argsConfig), type.name + '.' + fieldName + ' args must be an object with argument ' + 'names as keys.');
      field.args = Object.keys(argsConfig).map(function (argName) {
        (0, _assertValidName.assertValidName)(argName);
        var arg = argsConfig[argName];
        (0, _invariant2.default)(isInputType(arg.type), type.name + '.' + fieldName + '(' + argName + ':) argument type must be ' + ('Input Type but got: ' + String(arg.type) + '.'));
        return {
          name: argName,
          description: arg.description === undefined ? null : arg.description,
          type: arg.type,
          defaultValue: arg.defaultValue
        };
      });
    }
    resultFieldMap[fieldName] = field;
  });
  return resultFieldMap;
}

function isPlainObj(obj) {
  return obj && typeof obj === 'object' && !Array.isArray(obj);
}

// If a resolver is defined, it must be a function.
function isValidResolver(resolver) {
  return resolver == null || typeof resolver === 'function';
}

/**
 * Interface Type Definition
 *
 * When a field can return one of a heterogeneous set of types, a Interface type
 * is used to describe what types are possible, what fields are in common across
 * all types, as well as a function to determine which type is actually used
 * when the field is resolved.
 *
 * Example:
 *
 *     const EntityType = new GraphQLInterfaceType({
 *       name: 'Entity',
 *       fields: {
 *         name: { type: GraphQLString }
 *       }
 *     });
 *
 */
var GraphQLInterfaceType = exports.GraphQLInterfaceType = function () {
  function GraphQLInterfaceType(config) {
    _classCallCheck(this, GraphQLInterfaceType);

    (0, _assertValidName.assertValidName)(config.name);
    this.name = config.name;
    this.description = config.description;
    if (config.resolveType) {
      (0, _invariant2.default)(typeof config.resolveType === 'function', this.name + ' must provide "resolveType" as a function.');
    }
    this.resolveType = config.resolveType;
    this._typeConfig = config;
  }

  GraphQLInterfaceType.prototype.getFields = function getFields() {
    return this._fields || (this._fields = defineFieldMap(this, this._typeConfig.fields));
  };

  GraphQLInterfaceType.prototype.toString = function toString() {
    return this.name;
  };

  return GraphQLInterfaceType;
}();

// Also provide toJSON and inspect aliases for toString.


GraphQLInterfaceType.prototype.toJSON = GraphQLInterfaceType.prototype.inspect = GraphQLInterfaceType.prototype.toString;

/**
 * Union Type Definition
 *
 * When a field can return one of a heterogeneous set of types, a Union type
 * is used to describe what types are possible as well as providing a function
 * to determine which type is actually used when the field is resolved.
 *
 * Example:
 *
 *     const PetType = new GraphQLUnionType({
 *       name: 'Pet',
 *       types: [ DogType, CatType ],
 *       resolveType(value) {
 *         if (value instanceof Dog) {
 *           return DogType;
 *         }
 *         if (value instanceof Cat) {
 *           return CatType;
 *         }
 *       }
 *     });
 *
 */
var GraphQLUnionType = exports.GraphQLUnionType = function () {
  function GraphQLUnionType(config) {
    _classCallCheck(this, GraphQLUnionType);

    (0, _assertValidName.assertValidName)(config.name);
    this.name = config.name;
    this.description = config.description;
    if (config.resolveType) {
      (0, _invariant2.default)(typeof config.resolveType === 'function', this.name + ' must provide "resolveType" as a function.');
    }
    this.resolveType = config.resolveType;
    this._typeConfig = config;
  }

  GraphQLUnionType.prototype.getTypes = function getTypes() {
    return this._types || (this._types = defineTypes(this, this._typeConfig.types));
  };

  GraphQLUnionType.prototype.toString = function toString() {
    return this.name;
  };

  return GraphQLUnionType;
}();

// Also provide toJSON and inspect aliases for toString.


GraphQLUnionType.prototype.toJSON = GraphQLUnionType.prototype.inspect = GraphQLUnionType.prototype.toString;

function defineTypes(unionType, typesThunk) {
  var types = resolveThunk(typesThunk);

  (0, _invariant2.default)(Array.isArray(types) && types.length > 0, 'Must provide Array of types or a function which returns ' + ('such an array for Union ' + unionType.name + '.'));
  types.forEach(function (objType) {
    (0, _invariant2.default)(objType instanceof GraphQLObjectType, unionType.name + ' may only contain Object types, it cannot contain: ' + (String(objType) + '.'));
    if (typeof unionType.resolveType !== 'function') {
      (0, _invariant2.default)(typeof objType.isTypeOf === 'function', 'Union type "' + unionType.name + '" does not provide a "resolveType" ' + ('function and possible type "' + objType.name + '" does not provide an ') + '"isTypeOf" function. There is no way to resolve this possible type ' + 'during execution.');
    }
  });

  return types;
}

/**
 * Enum Type Definition
 *
 * Some leaf values of requests and input values are Enums. GraphQL serializes
 * Enum values as strings, however internally Enums can be represented by any
 * kind of type, often integers.
 *
 * Example:
 *
 *     const RGBType = new GraphQLEnumType({
 *       name: 'RGB',
 *       values: {
 *         RED: { value: 0 },
 *         GREEN: { value: 1 },
 *         BLUE: { value: 2 }
 *       }
 *     });
 *
 * Note: If a value is not provided in a definition, the name of the enum value
 * will be used as its internal value.
 */
var GraphQLEnumType /* <T> */ = exports.GraphQLEnumType = function () {
  function GraphQLEnumType(config /* <T> */) {
    _classCallCheck(this, GraphQLEnumType);

    this.name = config.name;
    (0, _assertValidName.assertValidName)(config.name, config.isIntrospection);
    this.description = config.description;
    this._values = defineEnumValues(this, config.values);
    this._enumConfig = config;
  }

  GraphQLEnumType.prototype.getValues = function getValues() {
    return this._values;
  };

  GraphQLEnumType.prototype.getValue = function getValue(name) {
    return this._getNameLookup()[name];
  };

  GraphQLEnumType.prototype.serialize = function serialize(value /* T */) {
    var enumValue = this._getValueLookup().get(value);
    return enumValue ? enumValue.name : null;
  };

  GraphQLEnumType.prototype.parseValue = function parseValue(value) /* T */{
    if (typeof value === 'string') {
      var enumValue = this._getNameLookup()[value];
      if (enumValue) {
        return enumValue.value;
      }
    }
  };

  GraphQLEnumType.prototype.parseLiteral = function parseLiteral(valueNode) /* T */{
    if (valueNode.kind === _kinds.ENUM) {
      var enumValue = this._getNameLookup()[valueNode.value];
      if (enumValue) {
        return enumValue.value;
      }
    }
  };

  GraphQLEnumType.prototype._getValueLookup = function _getValueLookup() {
    var _this = this;

    if (!this._valueLookup) {
      (function () {
        var lookup = new Map();
        _this.getValues().forEach(function (value) {
          lookup.set(value.value, value);
        });
        _this._valueLookup = lookup;
      })();
    }
    return this._valueLookup;
  };

  GraphQLEnumType.prototype._getNameLookup = function _getNameLookup() {
    var _this2 = this;

    if (!this._nameLookup) {
      (function () {
        var lookup = Object.create(null);
        _this2.getValues().forEach(function (value) {
          lookup[value.name] = value;
        });
        _this2._nameLookup = lookup;
      })();
    }
    return this._nameLookup;
  };

  GraphQLEnumType.prototype.toString = function toString() {
    return this.name;
  };

  return GraphQLEnumType;
}();

// Also provide toJSON and inspect aliases for toString.


GraphQLEnumType.prototype.toJSON = GraphQLEnumType.prototype.inspect = GraphQLEnumType.prototype.toString;

function defineEnumValues(type, valueMap /* <T> */
) {
  (0, _invariant2.default)(isPlainObj(valueMap), type.name + ' values must be an object with value names as keys.');
  var valueNames = Object.keys(valueMap);
  (0, _invariant2.default)(valueNames.length > 0, type.name + ' values must be an object with value names as keys.');
  return valueNames.map(function (valueName) {
    (0, _assertValidName.assertValidName)(valueName);
    var value = valueMap[valueName];
    (0, _invariant2.default)(isPlainObj(value), type.name + '.' + valueName + ' must refer to an object with a "value" key ' + ('representing an internal value but got: ' + String(value) + '.'));
    (0, _invariant2.default)(!value.hasOwnProperty('isDeprecated'), type.name + '.' + valueName + ' should provide "deprecationReason" instead ' + 'of "isDeprecated".');
    return {
      name: valueName,
      description: value.description,
      isDeprecated: Boolean(value.deprecationReason),
      deprecationReason: value.deprecationReason,
      value: (0, _isNullish2.default)(value.value) ? valueName : value.value
    };
  });
} /* <T> */


/**
 * Input Object Type Definition
 *
 * An input object defines a structured collection of fields which may be
 * supplied to a field argument.
 *
 * Using `NonNull` will ensure that a value must be provided by the query
 *
 * Example:
 *
 *     const GeoPoint = new GraphQLInputObjectType({
 *       name: 'GeoPoint',
 *       fields: {
 *         lat: { type: new GraphQLNonNull(GraphQLFloat) },
 *         lon: { type: new GraphQLNonNull(GraphQLFloat) },
 *         alt: { type: GraphQLFloat, defaultValue: 0 },
 *       }
 *     });
 *
 */
var GraphQLInputObjectType = exports.GraphQLInputObjectType = function () {
  function GraphQLInputObjectType(config) {
    _classCallCheck(this, GraphQLInputObjectType);

    (0, _assertValidName.assertValidName)(config.name);
    this.name = config.name;
    this.description = config.description;
    this._typeConfig = config;
  }

  GraphQLInputObjectType.prototype.getFields = function getFields() {
    return this._fields || (this._fields = this._defineFieldMap());
  };

  GraphQLInputObjectType.prototype._defineFieldMap = function _defineFieldMap() {
    var _this3 = this;

    var fieldMap = resolveThunk(this._typeConfig.fields);
    (0, _invariant2.default)(isPlainObj(fieldMap), this.name + ' fields must be an object with field names as keys or a ' + 'function which returns such an object.');
    var fieldNames = Object.keys(fieldMap);
    (0, _invariant2.default)(fieldNames.length > 0, this.name + ' fields must be an object with field names as keys or a ' + 'function which returns such an object.');
    var resultFieldMap = {};
    fieldNames.forEach(function (fieldName) {
      (0, _assertValidName.assertValidName)(fieldName);
      var field = _extends({}, fieldMap[fieldName], {
        name: fieldName
      });
      (0, _invariant2.default)(isInputType(field.type), _this3.name + '.' + fieldName + ' field type must be Input Type but ' + ('got: ' + String(field.type) + '.'));
      (0, _invariant2.default)(field.resolve == null, _this3.name + '.' + fieldName + ' field type has a resolve property, but ' + 'Input Types cannot define resolvers.');
      resultFieldMap[fieldName] = field;
    });
    return resultFieldMap;
  };

  GraphQLInputObjectType.prototype.toString = function toString() {
    return this.name;
  };

  return GraphQLInputObjectType;
}();

// Also provide toJSON and inspect aliases for toString.


GraphQLInputObjectType.prototype.toJSON = GraphQLInputObjectType.prototype.inspect = GraphQLInputObjectType.prototype.toString;

/**
 * List Modifier
 *
 * A list is a kind of type marker, a wrapping type which points to another
 * type. Lists are often created within the context of defining the fields of
 * an object type.
 *
 * Example:
 *
 *     const PersonType = new GraphQLObjectType({
 *       name: 'Person',
 *       fields: () => ({
 *         parents: { type: new GraphQLList(Person) },
 *         children: { type: new GraphQLList(Person) },
 *       })
 *     })
 *
 */
var GraphQLList = exports.GraphQLList = function () {
  function GraphQLList(type) {
    _classCallCheck(this, GraphQLList);

    (0, _invariant2.default)(isType(type), 'Can only create List of a GraphQLType but got: ' + String(type) + '.');
    this.ofType = type;
  }

  GraphQLList.prototype.toString = function toString() {
    return '[' + String(this.ofType) + ']';
  };

  return GraphQLList;
}();

// Also provide toJSON and inspect aliases for toString.


GraphQLList.prototype.toJSON = GraphQLList.prototype.inspect = GraphQLList.prototype.toString;

/**
 * Non-Null Modifier
 *
 * A non-null is a kind of type marker, a wrapping type which points to another
 * type. Non-null types enforce that their values are never null and can ensure
 * an error is raised if this ever occurs during a request. It is useful for
 * fields which you can make a strong guarantee on non-nullability, for example
 * usually the id field of a database row will never be null.
 *
 * Example:
 *
 *     const RowType = new GraphQLObjectType({
 *       name: 'Row',
 *       fields: () => ({
 *         id: { type: new GraphQLNonNull(GraphQLString) },
 *       })
 *     })
 *
 * Note: the enforcement of non-nullability occurs within the executor.
 */

var GraphQLNonNull = exports.GraphQLNonNull = function () {
  function GraphQLNonNull(type) {
    _classCallCheck(this, GraphQLNonNull);

    (0, _invariant2.default)(isType(type) && !(type instanceof GraphQLNonNull), 'Can only create NonNull of a Nullable GraphQLType but got: ' + (String(type) + '.'));
    this.ofType = type;
  }

  GraphQLNonNull.prototype.toString = function toString() {
    return this.ofType.toString() + '!';
  };

  return GraphQLNonNull;
}();

// Also provide toJSON and inspect aliases for toString.


GraphQLNonNull.prototype.toJSON = GraphQLNonNull.prototype.inspect = GraphQLNonNull.prototype.toString;