The graphql/error module is responsible for creating and formatting
GraphQL errors. You can import either from the graphql/error module, or from the root graphql module. For example:
import { GraphQLError } from "graphql" // ES6var { GraphQLError } = require("graphql") // CommonJS
class GraphQLErrorA representation of an error that occurred within GraphQL.
function syntaxErrorProduces a GraphQLError representing a syntax error.
function locatedErrorProduces a new GraphQLError aware of the location responsible for the error.
function formatErrorFormat an error according to the rules described by the Response Format.
class GraphQLError extends Error { constructor(   message: string,   nodes?: Array<any>,   stack?: ?string,   source?: Source,   positions?: Array<number>,   originalError?: ?Error,   extensions?: ?{ [key: string]: mixed } )}
A representation of an error that occurred within GraphQL. Contains
information about where in the query the error occurred for debugging. Most
commonly constructed with locatedError below.
function syntaxError(  source: Source,  position: number,  description: string): GraphQLError;
Produces a GraphQLError representing a syntax error, containing useful descriptive information about the syntax error's position in the source.
function locatedError(error: ?Error, nodes: Array<any>): GraphQLError {
Given an arbitrary Error, presumably thrown while attempting to execute a GraphQL operation, produce a new GraphQLError aware of the location in the document responsible for the original Error.
function formatError(error: GraphQLError): GraphQLFormattedError
type GraphQLFormattedError = {  message: string,  locations: ?Array<GraphQLErrorLocation>};
type GraphQLErrorLocation = {  line: number,  column: number};
Given a GraphQLError, format it according to the rules described by the Response Format, Errors section of the GraphQL Specification.