@nestjs/graphql/dist/type-factories/create-union-type.factory.js

Nest - modern, fast, powerful node.js web framework (@graphql)

/**
 * The API surface of this module has been heavily inspired by the "type-graphql" library (https://github.com/MichalLytek/type-graphql), originally designed & released by Michal Lytek.
 * In the v6 major release of NestJS, we introduced the code-first approach as a compatibility layer between this package and the `@nestjs/graphql` module.
 * Eventually, our team decided to reimplement all the features from scratch due to a lack of flexibility.
 * To avoid numerous breaking changes, the public API is backward-compatible and may resemble "type-graphql".
 */
import { LazyMetadataStorage } from '../schema-builder/storages/lazy-metadata.storage.js';
import { TypeMetadataStorage } from '../schema-builder/storages/type-metadata.storage.js';
/**
 * Creates a GraphQL union type composed of types references.
 * @param options
 */
export function createUnionType(options) {
    if (!options || typeof options.name !== 'string' || options.name === '') {
        throw new Error(`createUnionType requires an "options" object with a non-empty "name" (e.g. createUnionType({ name: 'MyUnion', types: () => [TypeA, TypeB] })).`);
    }
    if (typeof options.types !== 'function') {
        throw new Error(`createUnionType requires "options.types" to be a function returning the union member classes (e.g. types: () => [TypeA, TypeB]).`);
    }
    const { name, description, types, resolveType, registerIn, directives } = options;
    const id = Symbol(name);
    LazyMetadataStorage.store(() => TypeMetadataStorage.addUnionMetadata({
        id,
        name,
        description,
        typesFn: types,
        resolveType,
        registerIn,
        directives,
    }));
    return id;
}