graphql/utilities

The graphql/utilities module contains common useful computations to use with the GraphQL language and type objects. You can import either from the graphql/utilities module, or from the root graphql module. For example:

import { introspectionQuery } from 'graphql'; // ES6
const { introspectionQuery } = require('graphql'); // CommonJS

Overview

Introspection

• const introspectionQuery A GraphQL introspection query containing enough information to reproduce a type system.

• function buildClientSchema Produces a client schema given the result of querying a schema with introspectionQuery.

Schema Language

• function buildSchema Builds a Schema object from GraphQL schema language.

• function printSchema Prints the schema in a standard format.

• function printIntrospectionSchema Prints the introspection features of the schema in a standard format.

• function buildASTSchemaBuilds a schema from a parsed AST Schema.

• function typeFromAST Looks up a type referenced in an AST in the GraphQLSchema.

• function astFromValue Produces a GraphQL Input Value AST given a JavaScript value.

Visitors

• class TypeInfo Tracks type and field definitions during a visitor AST traversal..

Value Validation

• function isValidJSValue Determines if a JavaScript value is valid for a GraphQL type.

• function isValidLiteralValue Determines if a literal value from an AST is valid for a GraphQL type.

Introspection

introspectionQuery

const introspectionQuery: string;

A GraphQL query that queries a server’s introspection system for enough information to reproduce that server’s type system.

buildClientSchema

function buildClientSchema(introspection: IntrospectionQuery): GraphQLSchema;

Build a GraphQLSchema for use by client tools.

Given the result of a client running the introspection query, creates and returns a GraphQLSchema instance which can be then used with all GraphQL.js tools, but cannot be used to execute a query, as introspection does not represent the “resolver”, “parse” or “serialize” functions or any other server-internal mechanisms.

Schema Representation

buildSchema

function buildSchema(source: string | Source): GraphQLSchema;

Creates a GraphQLSchema object from GraphQL schema language. The schema will use default resolvers. For more detail on the GraphQL schema language, see the schema language docs or this schema language cheat sheet.

printSchema

function printSchema(schema: GraphQLSchema): string;

Prints the provided schema in the Schema Language format.

printIntrospectionSchema

function printIntrospectionSchema(schema: GraphQLSchema): string;

Prints the built-in introspection schema in the Schema Language format.

buildASTSchema

function buildASTSchema(
  ast: SchemaDocument,
  queryTypeName: string,
  mutationTypeName: string,
): GraphQLSchema;

This takes the ast of a schema document produced by parseSchemaIntoAST in graphql/language/schema and constructs a GraphQLSchema instance which can be then used with all GraphQL.js tools, but cannot be used to execute a query, as introspection does not represent the “resolver”, “parse” or “serialize” functions or any other server-internal mechanisms.

typeFromAST

function typeFromAST(schema: GraphQLSchema, inputTypeAST: Type): GraphQLType;

Given the name of a Type as it appears in a GraphQL AST and a Schema, return the corresponding GraphQLType from that schema.

astFromValue

function astFromValue(value: any, type: GraphQLInputType): Value;

Produces a GraphQL Input Value AST given a JavaScript value.

Optionally, a GraphQL type may be provided, which will be used to disambiguate between value primitives.

Visitors

TypeInfo

class TypeInfo {
  constructor(schema: GraphQLSchema);
  getType(): GraphQLOutputType;
  getParentType(): GraphQLCompositeType;
  getInputType(): GraphQLInputType;
  getFieldDef(): GraphQLFieldDefinition;
  getDirective(): GraphQLDirective;
  getArgument(): GraphQLArgument;
}

TypeInfo is a utility class which, given a GraphQL schema, can keep track of the current field and type definitions at any point in a GraphQL document AST during a recursive descent by calling enter(node) and leave(node).

Value Validation

isValidJSValue

function isValidJSValue(value: any, type: GraphQLInputType): string[];

Given a JavaScript value and a GraphQL type, determine if the value will be accepted for that type. This is primarily useful for validating the runtime values of query variables.

isValidLiteralValue

function isValidLiteralValue(type: GraphQLInputType, valueAST: Value): string[];

Utility for validators which determines if a value literal AST is valid given an input type.

Note that this only validates literal values, variables are assumed to provide values of the correct type.