graphql/utilities/typeFromAST.mjs

A Query Language and Runtime which can target any service.

import { inspect } from '../jsutils/inspect.mjs';
import { invariant } from '../jsutils/invariant.mjs';
import { Kind } from '../language/kinds.mjs';
import { GraphQLList, GraphQLNonNull } from '../type/definition.mjs';
/**
 * Given a Schema and an AST node describing a type, return a GraphQLType
 * definition which applies to that type. For example, if provided the parsed
 * AST node for `[User]`, a GraphQLList instance will be returned, containing
 * the type called "User" found in the schema. If a type called "User" is not
 * found in the schema, then undefined will be returned.
 */

export function typeFromAST(schema, typeNode) {
  let innerType;

  if (typeNode.kind === Kind.LIST_TYPE) {
    innerType = typeFromAST(schema, typeNode.type);
    return innerType && new GraphQLList(innerType);
  }

  if (typeNode.kind === Kind.NON_NULL_TYPE) {
    innerType = typeFromAST(schema, typeNode.type);
    return innerType && new GraphQLNonNull(innerType);
  } // istanbul ignore else (See: 'https://github.com/graphql/graphql-js/issues/2618')

  if (typeNode.kind === Kind.NAMED_TYPE) {
    return schema.getType(typeNode.name.value);
  } // istanbul ignore next (Not reachable. All possible type nodes have been considered)

  false || invariant(false, 'Unexpected type node: ' + inspect(typeNode));
}