getCombinedDecorator.ts

import { Field as TypeGraphQLField } from 'type-graphql';
import { Column as TypeORMColumn, ColumnType } from 'typeorm';

import { ColumnMetadata, FieldType } from '../metadata';
import { MethodDecoratorFactory } from '../utils';

import { WarthogField } from './WarthogField';

// Combine TypeORM, TypeGraphQL and Warthog decorators
export interface WarthogCombinedDecoratorOptions<T> {
  fieldType: FieldType; // This is the warthog field type
  warthogColumnMeta: T; // Warthog options like sort, filter, nullable
  gqlFieldType?: any; // This is the Type that will land in the GraphQL schmea
  dbType?: ColumnType;
  dbColumnOptions?: any; // Passed to TypeORM `Column` decorator
}

//
export function getCombinedDecorator<T extends Partial<ColumnMetadata>>({
  fieldType,
  warthogColumnMeta,
  gqlFieldType = String,
  dbType = 'varchar',
  dbColumnOptions: columnOptions = {}
}: WarthogCombinedDecoratorOptions<T>) {
  const nullableOption = warthogColumnMeta.nullable === true ? { nullable: true } : {};
  const defaultOption =
    typeof warthogColumnMeta.default !== 'undefined' ? { default: warthogColumnMeta.default } : {};
  const uniqueOption =
    typeof warthogColumnMeta.unique !== 'undefined' ? { unique: warthogColumnMeta.unique } : {};
  const tgqlDescriptionOption =
    typeof warthogColumnMeta.description !== 'undefined'
      ? { description: warthogColumnMeta.description }
      : {};
  const arrayOption = (warthogColumnMeta as any).array ? { array: true } : {};

  // TODO: Enable this when TypeORM is fixed: https://github.com/typeorm/typeorm/issues/5906
  // const typeOrmColumnOption =
  //   typeof warthogColumnMeta.description !== 'undefined'
  //     ? { column: warthogColumnMeta.description }
  //     : {};

  const exposeDB = !warthogColumnMeta.apiOnly;
  const exposeAPI = !warthogColumnMeta.dbOnly;

  // Warthog: start with the Warthog decorator that adds metadata for generating the GraphQL schema
  // for sorting, filtering, args, where inputs, etc...
  const decorators: any[] = [];

  if (exposeAPI) {
    decorators.push(WarthogField(fieldType, warthogColumnMeta));
  }

  // TypeGraphQL: next add the type-graphql decorator that generates the GraphQL type (or field within that type)
  // If an object is only writeable, don't add the `Field` decorators that will add it to the GraphQL type
  if (exposeAPI && !warthogColumnMeta.writeonly) {
    decorators.push(
      TypeGraphQLField(() => gqlFieldType, {
        ...nullableOption,
        ...defaultOption,
        ...tgqlDescriptionOption
      })
    );
  }

  // TypeORM: finally add the TypeORM decorator to describe the DB field
  if (exposeDB) {
    decorators.push(
      TypeORMColumn({
        type: dbType,
        ...nullableOption,
        ...defaultOption,
        ...columnOptions,
        ...uniqueOption,
        ...arrayOption
        // ...typeOrmColumnOption: // TODO: Enable this when TypeORM is fixed: https://github.com/typeorm/typeorm/issues/5906
      }) as MethodDecoratorFactory
    );
  }

  return decorators;
}