graphql

TypesSource
Search for an npm package
'use strict';
Object.defineProperty(exports, '__esModule', {
value: true,
});
exports.assertValidExecutionArguments = assertValidExecutionArguments;
exports.buildExecutionContext = buildExecutionContext;
exports.buildResolveInfo = buildResolveInfo;
exports.defaultTypeResolver = exports.defaultFieldResolver = void 0;
exports.execute = execute;
exports.executeSync = executeSync;
exports.getFieldDef = getFieldDef;
var _devAssert = require('../jsutils/devAssert.js');
var _inspect = require('../jsutils/inspect.js');
var _invariant = require('../jsutils/invariant.js');
var _isIterableObject = require('../jsutils/isIterableObject.js');
var _isObjectLike = require('../jsutils/isObjectLike.js');
var _isPromise = require('../jsutils/isPromise.js');
var _memoize = require('../jsutils/memoize3.js');
var _Path = require('../jsutils/Path.js');
var _promiseForObject = require('../jsutils/promiseForObject.js');
var _promiseReduce = require('../jsutils/promiseReduce.js');
var _GraphQLError = require('../error/GraphQLError.js');
var _locatedError = require('../error/locatedError.js');
var _ast = require('../language/ast.js');
var _kinds = require('../language/kinds.js');
var _definition = require('../type/definition.js');
var _introspection = require('../type/introspection.js');
var _validate = require('../type/validate.js');
var _collectFields = require('./collectFields.js');
var _values = require('./values.js');
/**
* A memoized collection of relevant subfields with regard to the return
* type. Memoizing ensures the subfields are not repeatedly calculated, which
* saves overhead when resolving lists of values.
*/
const collectSubfields = (0, _memoize.memoize3)(
(exeContext, returnType, fieldNodes) =>
(0, _collectFields.collectSubfields)(
exeContext.schema,
exeContext.fragments,
exeContext.variableValues,
returnType,
fieldNodes,
),
);
/**
* Terminology
*
* "Definitions" are the generic name for top-level statements in the document.
* Examples of this include:
* 1) Operations (such as a query)
* 2) Fragments
*
* "Operations" are a generic name for requests in the document.
* Examples of this include:
* 1) query,
* 2) mutation
*
* "Selections" are the definitions that can appear legally and at
* single level of the query. These include:
* 1) field references e.g `a`
* 2) fragment "spreads" e.g. `...c`
* 3) inline fragment "spreads" e.g. `...on Type { a }`
*/
/**
* Data that must be available at all points during query execution.
*
* Namely, schema of the type system that is currently executing,
* and the fragments defined in the query document
*/
/**
* Implements the "Executing requests" section of the GraphQL specification.
*
* Returns either a synchronous ExecutionResult (if all encountered resolvers
* are synchronous), or a Promise of an ExecutionResult that will eventually be
* resolved and never rejected.
*
* If the arguments to this function do not result in a legal execution context,
* a GraphQLError will be thrown immediately explaining the invalid input.
*/
function execute(args) {
// Temporary for v15 to v16 migration. Remove in v17
arguments.length < 2 ||
(0, _devAssert.devAssert)(
false,
'graphql@16 dropped long-deprecated support for positional arguments, please pass an object instead.',
);
const { schema, document, variableValues, rootValue } = args; // If arguments are missing or incorrect, throw an error.
assertValidExecutionArguments(schema, document, variableValues); // If a valid execution context cannot be created due to incorrect arguments,
// a "Response" with only errors is returned.
const exeContext = buildExecutionContext(args); // Return early errors if execution context failed.
if (!('schema' in exeContext)) {
return {
errors: exeContext,
};
} // Return a Promise that will eventually resolve to the data described by
// The "Response" section of the GraphQL specification.
//
// If errors are encountered while executing a GraphQL field, only that
// field and its descendants will be omitted, and sibling fields will still
// be executed. An execution which encounters errors will still result in a
// resolved Promise.
//
// Errors from sub-fields of a NonNull type may propagate to the top level,
// at which point we still log the error and null the parent field, which
// in this case is the entire response.
try {
const { operation } = exeContext;
const result = executeOperation(exeContext, operation, rootValue);
if ((0, _isPromise.isPromise)(result)) {
return result.then(
(data) => buildResponse(data, exeContext.errors),
(error) => {
exeContext.errors.push(error);
return buildResponse(null, exeContext.errors);
},
);
}
return buildResponse(result, exeContext.errors);
} catch (error) {
exeContext.errors.push(error);
return buildResponse(null, exeContext.errors);
}
}
/**
* Also implements the "Executing requests" section of the GraphQL specification.
* However, it guarantees to complete synchronously (or throw an error) assuming
* that all field resolvers are also synchronous.
*/
function executeSync(args) {
const result = execute(args); // Assert that the execution was synchronous.
if ((0, _isPromise.isPromise)(result)) {
throw new Error('GraphQL execution failed to complete synchronously.');
}
return result;
}
/**
* Given a completed execution context and data, build the `{ errors, data }`
* response defined by the "Response" section of the GraphQL specification.
*/
function buildResponse(data, errors) {
return errors.length === 0
? {
data,
}
: {
errors,
data,
};
}
/**
* Essential assertions before executing to provide developer feedback for
* improper use of the GraphQL library.
*
* @internal
*/
function assertValidExecutionArguments(schema, document, rawVariableValues) {
document || (0, _devAssert.devAssert)(false, 'Must provide document.'); // If the schema used for execution is invalid, throw an error.
(0, _validate.assertValidSchema)(schema); // Variables, if provided, must be an object.
rawVariableValues == null ||
(0, _isObjectLike.isObjectLike)(rawVariableValues) ||
(0, _devAssert.devAssert)(
false,
'Variables must be provided as an Object where each property is a variable value. Perhaps look to see if an unparsed JSON string was provided.',
);
}
/**
* Constructs a ExecutionContext object from the arguments passed to
* execute, which we will pass throughout the other execution methods.
*
* Throws a GraphQLError if a valid execution context cannot be created.
*
* @internal
*/
function buildExecutionContext(args) {
var _definition$name, _operation$variableDe;
const {
schema,
document,
rootValue,
contextValue,
variableValues: rawVariableValues,
operationName,
fieldResolver,
typeResolver,
subscribeFieldResolver,
} = args;
let operation;
const fragments = Object.create(null);
for (const definition of document.definitions) {
switch (definition.kind) {
case _kinds.Kind.OPERATION_DEFINITION:
if (operationName == null) {
if (operation !== undefined) {
return [
new _GraphQLError.GraphQLError(
'Must provide operation name if query contains multiple operations.',
),
];
}
operation = definition;
} else if (
((_definition$name = definition.name) === null ||
_definition$name === void 0
? void 0
: _definition$name.value) === operationName
) {
operation = definition;
}
break;
case _kinds.Kind.FRAGMENT_DEFINITION:
fragments[definition.name.value] = definition;
break;
default: // ignore non-executable definitions
}
}
if (!operation) {
if (operationName != null) {
return [
new _GraphQLError.GraphQLError(
`Unknown operation named "${operationName}".`,
),
];
}
return [new _GraphQLError.GraphQLError('Must provide an operation.')];
} // FIXME: https://github.com/graphql/graphql-js/issues/2203
/* c8 ignore next */
const variableDefinitions =
(_operation$variableDe = operation.variableDefinitions) !== null &&
_operation$variableDe !== void 0
? _operation$variableDe
: [];
const coercedVariableValues = (0, _values.getVariableValues)(
schema,
variableDefinitions,
rawVariableValues !== null && rawVariableValues !== void 0
? rawVariableValues
: {},
{
maxErrors: 50,
},
);
if (coercedVariableValues.errors) {
return coercedVariableValues.errors;
}
return {
schema,
fragments,
rootValue,
contextValue,
operation,
variableValues: coercedVariableValues.coerced,
fieldResolver:
fieldResolver !== null && fieldResolver !== void 0
? fieldResolver
: defaultFieldResolver,
typeResolver:
typeResolver !== null && typeResolver !== void 0
? typeResolver
: defaultTypeResolver,
subscribeFieldResolver:
subscribeFieldResolver !== null && subscribeFieldResolver !== void 0
? subscribeFieldResolver
: defaultFieldResolver,
errors: [],
};
}
/**
* Implements the "Executing operations" section of the spec.
*/
function executeOperation(exeContext, operation, rootValue) {
const rootType = exeContext.schema.getRootType(operation.operation);
if (rootType == null) {
throw new _GraphQLError.GraphQLError(
`Schema is not configured to execute ${operation.operation} operation.`,
{
nodes: operation,
},
);
}
const rootFields = (0, _collectFields.collectFields)(
exeContext.schema,
exeContext.fragments,
exeContext.variableValues,
rootType,
operation.selectionSet,
);
const path = undefined;
switch (operation.operation) {
case _ast.OperationTypeNode.QUERY:
return executeFields(exeContext, rootType, rootValue, path, rootFields);
case _ast.OperationTypeNode.MUTATION:
return executeFieldsSerially(
exeContext,
rootType,
rootValue,
path,
rootFields,
);
case _ast.OperationTypeNode.SUBSCRIPTION:
// TODO: deprecate `subscribe` and move all logic here
// Temporary solution until we finish merging execute and subscribe together
return executeFields(exeContext, rootType, rootValue, path, rootFields);
}
}
/**
* Implements the "Executing selection sets" section of the spec
* for fields that must be executed serially.
*/
function executeFieldsSerially(
exeContext,
parentType,
sourceValue,
path,
fields,
) {
return (0, _promiseReduce.promiseReduce)(
fields.entries(),
(results, [responseName, fieldNodes]) => {
const fieldPath = (0, _Path.addPath)(path, responseName, parentType.name);
const result = executeField(
exeContext,
parentType,
sourceValue,
fieldNodes,
fieldPath,
);
if (result === undefined) {
return results;
}
if ((0, _isPromise.isPromise)(result)) {
return result.then((resolvedResult) => {
results[responseName] = resolvedResult;
return results;
});
}
results[responseName] = result;
return results;
},
Object.create(null),
);
}
/**
* Implements the "Executing selection sets" section of the spec
* for fields that may be executed in parallel.
*/
function executeFields(exeContext, parentType, sourceValue, path, fields) {
const results = Object.create(null);
let containsPromise = false;
for (const [responseName, fieldNodes] of fields.entries()) {
const fieldPath = (0, _Path.addPath)(path, responseName, parentType.name);
const result = executeField(
exeContext,
parentType,
sourceValue,
fieldNodes,
fieldPath,
);
if (result !== undefined) {
results[responseName] = result;
if ((0, _isPromise.isPromise)(result)) {
containsPromise = true;
}
}
} // If there are no promises, we can just return the object
if (!containsPromise) {
return results;
} // Otherwise, results is a map from field name to the result of resolving that
// field, which is possibly a promise. Return a promise that will return this
// same map, but with any promises replaced with the values they resolved to.
return (0, _promiseForObject.promiseForObject)(results);
}
/**
* Implements the "Executing fields" section of the spec
* In particular, this function figures out the value that the field returns by
* calling its resolve function, then calls completeValue to complete promises,
* serialize scalars, or execute the sub-selection-set for objects.
*/
function executeField(exeContext, parentType, source, fieldNodes, path) {
var _fieldDef$resolve;
const fieldDef = getFieldDef(exeContext.schema, parentType, fieldNodes[0]);
if (!fieldDef) {
return;
}
const returnType = fieldDef.type;
const resolveFn =
(_fieldDef$resolve = fieldDef.resolve) !== null &&
_fieldDef$resolve !== void 0
? _fieldDef$resolve
: exeContext.fieldResolver;
const info = buildResolveInfo(
exeContext,
fieldDef,
fieldNodes,
parentType,
path,
); // Get the resolve function, regardless of if its result is normal or abrupt (error).
try {
// Build a JS object of arguments from the field.arguments AST, using the
// variables scope to fulfill any variable references.
// TODO: find a way to memoize, in case this field is within a List type.
const args = (0, _values.getArgumentValues)(
fieldDef,
fieldNodes[0],
exeContext.variableValues,
); // The resolve function's optional third argument is a context value that
// is provided to every resolve function within an execution. It is commonly
// used to represent an authenticated user, or request-specific caches.
const contextValue = exeContext.contextValue;
const result = resolveFn(source, args, contextValue, info);
let completed;
if ((0, _isPromise.isPromise)(result)) {
completed = result.then((resolved) =>
completeValue(exeContext, returnType, fieldNodes, info, path, resolved),
);
} else {
completed = completeValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result,
);
}
if ((0, _isPromise.isPromise)(completed)) {
// Note: we don't rely on a `catch` method, but we do expect "thenable"
// to take a second callback for the error case.
return completed.then(undefined, (rawError) => {
const error = (0, _locatedError.locatedError)(
rawError,
fieldNodes,
(0, _Path.pathToArray)(path),
);
return handleFieldError(error, returnType, exeContext);
});
}
return completed;
} catch (rawError) {
const error = (0, _locatedError.locatedError)(
rawError,
fieldNodes,
(0, _Path.pathToArray)(path),
);
return handleFieldError(error, returnType, exeContext);
}
}
/**
* @internal
*/
function buildResolveInfo(exeContext, fieldDef, fieldNodes, parentType, path) {
// The resolve function's optional fourth argument is a collection of
// information about the current execution state.
return {
fieldName: fieldDef.name,
fieldNodes,
returnType: fieldDef.type,
parentType,
path,
schema: exeContext.schema,
fragments: exeContext.fragments,
rootValue: exeContext.rootValue,
operation: exeContext.operation,
variableValues: exeContext.variableValues,
};
}
function handleFieldError(error, returnType, exeContext) {
// If the field type is non-nullable, then it is resolved without any
// protection from errors, however it still properly locates the error.
if ((0, _definition.isNonNullType)(returnType)) {
throw error;
} // Otherwise, error protection is applied, logging the error and resolving
// a null value for this field if one is encountered.
exeContext.errors.push(error);
return null;
}
/**
* Implements the instructions for completeValue as defined in the
* "Value Completion" section of the spec.
*
* If the field type is Non-Null, then this recursively completes the value
* for the inner type. It throws a field error if that completion returns null,
* as per the "Nullability" section of the spec.
*
* If the field type is a List, then this recursively completes the value
* for the inner type on each item in the list.
*
* If the field type is a Scalar or Enum, ensures the completed value is a legal
* value of the type by calling the `serialize` method of GraphQL type
* definition.
*
* If the field is an abstract type, determine the runtime type of the value
* and then complete based on that type
*
* Otherwise, the field type expects a sub-selection set, and will complete the
* value by executing all sub-selections.
*/
function completeValue(exeContext, returnType, fieldNodes, info, path, result) {
// If result is an Error, throw a located error.
if (result instanceof Error) {
throw result;
} // If field type is NonNull, complete for inner type, and throw field error
// if result is null.
if ((0, _definition.isNonNullType)(returnType)) {
const completed = completeValue(
exeContext,
returnType.ofType,
fieldNodes,
info,
path,
result,
);
if (completed === null) {
throw new Error(
`Cannot return null for non-nullable field ${info.parentType.name}.${info.fieldName}.`,
);
}
return completed;
} // If result value is null or undefined then return null.
if (result == null) {
return null;
} // If field type is List, complete each item in the list with the inner type
if ((0, _definition.isListType)(returnType)) {
return completeListValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result,
);
} // If field type is a leaf type, Scalar or Enum, serialize to a valid value,
// returning null if serialization is not possible.
if ((0, _definition.isLeafType)(returnType)) {
return completeLeafValue(returnType, result);
} // If field type is an abstract type, Interface or Union, determine the
// runtime Object type and complete for that type.
if ((0, _definition.isAbstractType)(returnType)) {
return completeAbstractValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result,
);
} // If field type is Object, execute and complete all sub-selections.
if ((0, _definition.isObjectType)(returnType)) {
return completeObjectValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result,
);
}
/* c8 ignore next 6 */
// Not reachable, all possible output types have been considered.
false ||
(0, _invariant.invariant)(
false,
'Cannot complete value of unexpected output type: ' +
(0, _inspect.inspect)(returnType),
);
}
/**
* Complete a list value by completing each item in the list with the
* inner type
*/
function completeListValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result,
) {
if (!(0, _isIterableObject.isIterableObject)(result)) {
throw new _GraphQLError.GraphQLError(
`Expected Iterable, but did not find one for field "${info.parentType.name}.${info.fieldName}".`,
);
} // This is specified as a simple map, however we're optimizing the path
// where the list contains no Promises by avoiding creating another Promise.
const itemType = returnType.ofType;
let containsPromise = false;
const completedResults = Array.from(result, (item, index) => {
// No need to modify the info object containing the path,
// since from here on it is not ever accessed by resolver functions.
const itemPath = (0, _Path.addPath)(path, index, undefined);
try {
let completedItem;
if ((0, _isPromise.isPromise)(item)) {
completedItem = item.then((resolved) =>
completeValue(
exeContext,
itemType,
fieldNodes,
info,
itemPath,
resolved,
),
);
} else {
completedItem = completeValue(
exeContext,
itemType,
fieldNodes,
info,
itemPath,
item,
);
}
if ((0, _isPromise.isPromise)(completedItem)) {
containsPromise = true; // Note: we don't rely on a `catch` method, but we do expect "thenable"
// to take a second callback for the error case.
return completedItem.then(undefined, (rawError) => {
const error = (0, _locatedError.locatedError)(
rawError,
fieldNodes,
(0, _Path.pathToArray)(itemPath),
);
return handleFieldError(error, itemType, exeContext);
});
}
return completedItem;
} catch (rawError) {
const error = (0, _locatedError.locatedError)(
rawError,
fieldNodes,
(0, _Path.pathToArray)(itemPath),
);
return handleFieldError(error, itemType, exeContext);
}
});
return containsPromise ? Promise.all(completedResults) : completedResults;
}
/**
* Complete a Scalar or Enum by serializing to a valid value, returning
* null if serialization is not possible.
*/
function completeLeafValue(returnType, result) {
const serializedResult = returnType.serialize(result);
if (serializedResult == null) {
throw new Error(
`Expected \`${(0, _inspect.inspect)(returnType)}.serialize(${(0,
_inspect.inspect)(result)})\` to ` +
`return non-nullable value, returned: ${(0, _inspect.inspect)(
serializedResult,
)}`,
);
}
return serializedResult;
}
/**
* Complete a value of an abstract type by determining the runtime object type
* of that value, then complete the value for that type.
*/
function completeAbstractValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result,
) {
var _returnType$resolveTy;
const resolveTypeFn =
(_returnType$resolveTy = returnType.resolveType) !== null &&
_returnType$resolveTy !== void 0
? _returnType$resolveTy
: exeContext.typeResolver;
const contextValue = exeContext.contextValue;
const runtimeType = resolveTypeFn(result, contextValue, info, returnType);
if ((0, _isPromise.isPromise)(runtimeType)) {
return runtimeType.then((resolvedRuntimeType) =>
completeObjectValue(
exeContext,
ensureValidRuntimeType(
resolvedRuntimeType,
exeContext,
returnType,
fieldNodes,
info,
result,
),
fieldNodes,
info,
path,
result,
),
);
}
return completeObjectValue(
exeContext,
ensureValidRuntimeType(
runtimeType,
exeContext,
returnType,
fieldNodes,
info,
result,
),
fieldNodes,
info,
path,
result,
);
}
function ensureValidRuntimeType(
runtimeTypeName,
exeContext,
returnType,
fieldNodes,
info,
result,
) {
if (runtimeTypeName == null) {
throw new _GraphQLError.GraphQLError(
`Abstract type "${returnType.name}" must resolve to an Object type at runtime for field "${info.parentType.name}.${info.fieldName}". Either the "${returnType.name}" type should provide a "resolveType" function or each possible type should provide an "isTypeOf" function.`,
fieldNodes,
);
} // releases before 16.0.0 supported returning `GraphQLObjectType` from `resolveType`
// TODO: remove in 17.0.0 release
if ((0, _definition.isObjectType)(runtimeTypeName)) {
throw new _GraphQLError.GraphQLError(
'Support for returning GraphQLObjectType from resolveType was removed in graphql-js@16.0.0 please return type name instead.',
);
}
if (typeof runtimeTypeName !== 'string') {
throw new _GraphQLError.GraphQLError(
`Abstract type "${returnType.name}" must resolve to an Object type at runtime for field "${info.parentType.name}.${info.fieldName}" with ` +
`value ${(0, _inspect.inspect)(result)}, received "${(0,
_inspect.inspect)(runtimeTypeName)}".`,
);
}
const runtimeType = exeContext.schema.getType(runtimeTypeName);
if (runtimeType == null) {
throw new _GraphQLError.GraphQLError(
`Abstract type "${returnType.name}" was resolved to a type "${runtimeTypeName}" that does not exist inside the schema.`,
{
nodes: fieldNodes,
},
);
}
if (!(0, _definition.isObjectType)(runtimeType)) {
throw new _GraphQLError.GraphQLError(
`Abstract type "${returnType.name}" was resolved to a non-object type "${runtimeTypeName}".`,
{
nodes: fieldNodes,
},
);
}
if (!exeContext.schema.isSubType(returnType, runtimeType)) {
throw new _GraphQLError.GraphQLError(
`Runtime Object type "${runtimeType.name}" is not a possible type for "${returnType.name}".`,
{
nodes: fieldNodes,
},
);
}
return runtimeType;
}
/**
* Complete an Object value by executing all sub-selections.
*/
function completeObjectValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result,
) {
// Collect sub-fields to execute to complete this value.
const subFieldNodes = collectSubfields(exeContext, returnType, fieldNodes); // If there is an isTypeOf predicate function, call it with the
// current result. If isTypeOf returns false, then raise an error rather
// than continuing execution.
if (returnType.isTypeOf) {
const isTypeOf = returnType.isTypeOf(result, exeContext.contextValue, info);
if ((0, _isPromise.isPromise)(isTypeOf)) {
return isTypeOf.then((resolvedIsTypeOf) => {
if (!resolvedIsTypeOf) {
throw invalidReturnTypeError(returnType, result, fieldNodes);
}
return executeFields(
exeContext,
returnType,
result,
path,
subFieldNodes,
);
});
}
if (!isTypeOf) {
throw invalidReturnTypeError(returnType, result, fieldNodes);
}
}
return executeFields(exeContext, returnType, result, path, subFieldNodes);
}
function invalidReturnTypeError(returnType, result, fieldNodes) {
return new _GraphQLError.GraphQLError(
`Expected value of type "${returnType.name}" but got: ${(0,
_inspect.inspect)(result)}.`,
{
nodes: fieldNodes,
},
);
}
/**
* If a resolveType function is not given, then a default resolve behavior is
* used which attempts two strategies:
*
* First, See if the provided value has a `__typename` field defined, if so, use
* that value as name of the resolved type.
*
* Otherwise, test each possible type for the abstract type by calling
* isTypeOf for the object being coerced, returning the first type that matches.
*/
const defaultTypeResolver = function (value, contextValue, info, abstractType) {
// First, look for `__typename`.
if (
(0, _isObjectLike.isObjectLike)(value) &&
typeof value.__typename === 'string'
) {
return value.__typename;
} // Otherwise, test each possible type.
const possibleTypes = info.schema.getPossibleTypes(abstractType);
const promisedIsTypeOfResults = [];
for (let i = 0; i < possibleTypes.length; i++) {
const type = possibleTypes[i];
if (type.isTypeOf) {
const isTypeOfResult = type.isTypeOf(value, contextValue, info);
if ((0, _isPromise.isPromise)(isTypeOfResult)) {
promisedIsTypeOfResults[i] = isTypeOfResult;
} else if (isTypeOfResult) {
return type.name;
}
}
}
if (promisedIsTypeOfResults.length) {
return Promise.all(promisedIsTypeOfResults).then((isTypeOfResults) => {
for (let i = 0; i < isTypeOfResults.length; i++) {
if (isTypeOfResults[i]) {
return possibleTypes[i].name;
}
}
});
}
};
/**
* If a resolve function is not given, then a default resolve behavior is used
* which takes the property of the source object of the same name as the field
* and returns it as the result, or if it's a function, returns the result
* of calling that function while passing along args and context value.
*/
exports.defaultTypeResolver = defaultTypeResolver;
const defaultFieldResolver = function (source, args, contextValue, info) {
// ensure source is a value for which property access is acceptable.
if ((0, _isObjectLike.isObjectLike)(source) || typeof source === 'function') {
const property = source[info.fieldName];
if (typeof property === 'function') {
return source[info.fieldName](args, contextValue, info);
}
return property;
}
};
/**
* This method looks up the field on the given type definition.
* It has special casing for the three introspection fields,
* __schema, __type and __typename. __typename is special because
* it can always be queried as a field, even in situations where no
* other fields are allowed, like on a Union. __schema and __type
* could get automatically added to the query type, but that would
* require mutating type definitions, which would cause issues.
*
* @internal
*/
exports.defaultFieldResolver = defaultFieldResolver;
function getFieldDef(schema, parentType, fieldNode) {
const fieldName = fieldNode.name.value;
if (
fieldName === _introspection.SchemaMetaFieldDef.name &&
schema.getQueryType() === parentType
) {
return _introspection.SchemaMetaFieldDef;
} else if (
fieldName === _introspection.TypeMetaFieldDef.name &&
schema.getQueryType() === parentType
) {
return _introspection.TypeMetaFieldDef;
} else if (fieldName === _introspection.TypeNameMetaFieldDef.name) {
return _introspection.TypeNameMetaFieldDef;
}
return parentType.getFields()[fieldName];
}