`graphql/type`

The graphql/type entry point defines schemas, type constructors, directives, introspection types, predicates, assertions, and TypeScript types used when building GraphQL schemas programmatically.

import { GraphQLSchema, GraphQLObjectType, GraphQLString } from 'graphql/type';

The same exports are also available from the root graphql entry point.

Schema Exports
Type Constructor Exports
Type Predicate and Assertion Exports
Field-like Schema Element Exports
Type Unwrapping and Requirement Helpers
Scalar Exports
Directive Exports
Introspection Exports
Name Assertion Exports

Schema Exports

Export	Kind	Description
`GraphQLSchema` Changed in v17	Class	GraphQL schema object containing root operation types, reachable types, directives, and extension metadata. v17 includes `getField()` for ordinary and meta fields.
`isSchema()`	Predicate	Checks whether a value is a `GraphQLSchema`.
`assertSchema()`	Assertion	Returns a `GraphQLSchema` or throws.
`validateSchema()`	Function	Returns schema validation errors.
`assertValidSchema()`	Function	Throws when schema validation fails.
`GraphQLSchemaConfig`	Type	Constructor configuration for `GraphQLSchema`.
`GraphQLSchemaExtensions`	Type	Schema extension metadata map.

const schema = new GraphQLSchema({
  query: QueryType,
  mutation: MutationType,
});

Type Constructor Exports

Argument and input field configs in v17 prefer default: { value } or default: { literal }. The legacy defaultValue config still works in v17 and is deprecated for removal in v18.

Export	Kind	Description
`GraphQLScalarType` Changed in v17	Class	Defines custom leaf values. v17 prefers the `coerce*` and `valueToLiteral` method names.
`GraphQLObjectType`	Class	Defines object types with fields.
`GraphQLInterfaceType`	Class	Defines shared fields and abstract runtime resolution.
`GraphQLUnionType`	Class	Defines abstract types with possible object members.
`GraphQLEnumType`	Class	Defines finite named values.
`GraphQLInputObjectType`	Class	Defines structured input values.
`GraphQLList`	Class	Wraps another type as a list.
`GraphQLNonNull`	Class	Wraps another type as non-null.

const QueryType = new GraphQLObjectType({
  name: 'Query',
  fields: {
    greeting: {
      type: GraphQLString,
      resolve: () => 'hello',
    },
  },
});

Type Predicate and Assertion Exports

Predicate	Assertion	Description
`isType()`	`assertType()`	Any GraphQL named or wrapping type.
`isScalarType()`	`assertScalarType()`	`GraphQLScalarType`.
`isObjectType()`	`assertObjectType()`	`GraphQLObjectType`.
`isInterfaceType()`	`assertInterfaceType()`	`GraphQLInterfaceType`.
`isUnionType()`	`assertUnionType()`	`GraphQLUnionType`.
`isEnumType()`	`assertEnumType()`	`GraphQLEnumType`.
`isInputObjectType()`	`assertInputObjectType()`	`GraphQLInputObjectType`.
`isListType()`	`assertListType()`	`GraphQLList`.
`isNonNullType()`	`assertNonNullType()`	`GraphQLNonNull`.
`isInputType()`	`assertInputType()`	Any type valid in an input position.
`isOutputType()`	`assertOutputType()`	Any type valid in an output position.
`isLeafType()`	`assertLeafType()`	Scalar or enum type.
`isCompositeType()`	`assertCompositeType()`	Object, interface, or union type.
`isAbstractType()`	`assertAbstractType()`	Interface or union type.
`isWrappingType()`	`assertWrappingType()`	List or non-null wrapper.
`isNullableType()`	`assertNullableType()`	Any type except non-null wrappers.
`isNamedType()`	`assertNamedType()`	Any named type.

import { assertObjectType } from 'graphql';
 
const objectType = assertObjectType(schema.getType('User'));

Field-like Schema Element Exports

Export	Kind	Description
`GraphQLField` New in v17	Type	Runtime field definition returned from object and interface field maps.
`GraphQLArgument` New in v17	Type	Runtime field, directive, or fragment argument definition.
`GraphQLInputField` New in v17	Type	Runtime input object field definition.
`GraphQLEnumValue` New in v17	Type	Runtime enum value definition.
`isField()` / `assertField()` New in v17	Predicate and assertion	Checks `GraphQLField` instances.
`isArgument()` / `assertArgument()` New in v17	Predicate and assertion	Checks `GraphQLArgument` instances.
`isInputField()` / `assertInputField()` New in v17	Predicate and assertion	Checks `GraphQLInputField` instances.
`isEnumValue()` / `assertEnumValue()` New in v17	Predicate and assertion	Checks `GraphQLEnumValue` instances.

const userType = assertObjectType(schema.getType('User'));
const nameField = userType.getFields().name;
 
if (isField(nameField)) {
  console.log(nameField.type.toString());
}

Type Unwrapping and Requirement Helpers

Export	Kind	Description
`getNullableType()`	Function	Removes one or more `GraphQLNonNull` wrappers.
`getNamedType()`	Function	Removes all list and non-null wrappers.
`isRequiredArgument()` Changed in v17	Function	Checks whether an argument is non-null and has no default.
`isRequiredInputField()` Changed in v17	Function	Checks whether an input field is non-null and has no default.
`resolveObjMapThunk()`	Function	Resolves a lazy object map used by schema config APIs.
`resolveReadonlyArrayThunk()`	Function	Resolves a lazy readonly array used by schema config APIs.
`ThunkObjMap`	Type	Object map or function returning one.
`ThunkReadonlyArray`	Type	Readonly array or function returning one.

Scalar Exports

v17 scalar configs prefer coerceOutputValue, coerceInputValue, coerceInputLiteral, and valueToLiteral. Legacy names (serialize, parseValue, parseLiteral) remain available for compatibility and are deprecated for removal in v18.

Export	Kind	Description
`GraphQLInt`	Scalar	32-bit signed integer.
`GraphQLFloat`	Scalar	Double-precision finite number.
`GraphQLString`	Scalar	UTF-8 string.
`GraphQLBoolean`	Scalar	Boolean value.
`GraphQLID`	Scalar	ID value serialized as a string.
`specifiedScalarTypes`	Array	Built-in scalar instances.
`isSpecifiedScalarType()`	Predicate	Checks built-in scalar instances.
`GRAPHQL_MAX_INT`	Constant	Maximum GraphQL `Int` value.
`GRAPHQL_MIN_INT`	Constant	Minimum GraphQL `Int` value.

import { GraphQLScalarType, Kind } from 'graphql';
 
const DateTime = new GraphQLScalarType({
  name: 'DateTime',
  coerceOutputValue(value) {
    return new Date(value).toISOString();
  },
  coerceInputValue(value) {
    const date = new Date(value);
    if (Number.isNaN(date.getTime())) {
      throw new TypeError('DateTime cannot represent an invalid date');
    }
    return date;
  },
  valueToLiteral(value) {
    return { kind: Kind.STRING, value: new Date(value).toISOString() };
  },
});

Directive Exports

Export	Kind	Description
`GraphQLDirective`	Class	Runtime directive definition.
`isDirective()`	Predicate	Checks `GraphQLDirective`.
`assertDirective()`	Assertion	Returns a `GraphQLDirective` or throws.
`specifiedDirectives`	Array	Directives included by default in schemas.
`isSpecifiedDirective()`	Predicate	Checks whether a directive is specified.
`GraphQLIncludeDirective`	Directive	Built-in `@include`.
`GraphQLSkipDirective`	Directive	Built-in `@skip`.
`GraphQLDeprecatedDirective`	Directive	Built-in `@deprecated`.
`GraphQLSpecifiedByDirective`	Directive	Built-in `@specifiedBy`.
`GraphQLOneOfDirective`	Directive	Built-in `@oneOf`.
`GraphQLDeferDirective` New in v17	Directive	Experimental `@defer`; not included in `specifiedDirectives`.
`GraphQLStreamDirective` New in v17	Directive	Experimental `@stream`; not included in `specifiedDirectives`.
`DEFAULT_DEPRECATION_REASON`	Constant	Default reason text for deprecations.

GraphQLDirective includes deprecationReason and extensionASTNodes. See Directives on Directives for directive deprecation metadata.

Introspection Exports

Export	Kind	Description
`introspectionTypes`	Array	Built-in introspection type instances.
`isIntrospectionType()`	Predicate	Checks built-in introspection types.
`__Schema`	Object type	Introspection schema type.
`__Directive`	Object type	Introspection directive type.
`__DirectiveLocation`	Enum type	Introspection directive location enum.
`__Type`	Object type	Introspection type type.
`__Field`	Object type	Introspection field type.
`__InputValue`	Object type	Introspection argument/input field type.
`__EnumValue`	Object type	Introspection enum value type.
`__TypeKind`	Enum type	Introspection type kind enum.
`TypeKind`	Const object	Type kind constants used by introspection.
`SchemaMetaFieldDef` Changed in v17	Field	Definition for `__schema`. In v17 this is a `GraphQLField`.
`TypeMetaFieldDef` Changed in v17	Field	Definition for `__type`. In v17 this is a `GraphQLField`.
`TypeNameMetaFieldDef` Changed in v17	Field	Definition for `__typename`. In v17 this is a `GraphQLField`.

Name Assertion Exports

Export	Kind	Description
`assertName()`	Function	Asserts that a string is a valid GraphQL name and returns it.
`assertEnumValueName()`	Function	Asserts that a string is a valid enum value name.

Use these instead of the removed utility exports assertValidName() and isValidNameError().

graphql/language graphql/utilities

graphql/type

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