Make every field in InputType nullable

[korki43]

Is it possible to make every field in an InputType (or ArgsType) nullable?

Example: I have a CreateUserInput which extends on User and want a MutateUserInput which has all the fields the original one has but nullable.

@ObjectType()
@InputType()
class User {
  @Field()
  username: string;

  @Field({ nullable: true })
  optionalField?: string;
}

@InputType()
class CreateUserInput extends User {
  @Field()
  @MinLength(8) // validation, ...
  password: string;
}

// i want this - but I don't want to type this
@InputType()
class MutateUser {
  @Field({ nullable: true })
  username: string;

  @Field({ nullable: true })
  optionalField?: string;

  @Field({ nullable: true })
  @MinLength(3)
  password: string;
}

[MichalLytek]

Nope, there's no built-in way for doing that.

[MichalLytek]

Unofficial workaround implementation:

export function PartialType<TClassType extends ConstructorType>(BaseClass: TClassType) {
  @ObjectType()
  @InputType()
  class PartialTypeClass extends BaseClass {}

  const fieldsMetadata: FieldMetadata[] = [];
  let superClass = BaseClass;
  while (superClass.prototype !== undefined) {
    fieldsMetadata.push(...getMetadataStorage().fields.filter((it) => it.target === superClass));
    superClass = Object.getPrototypeOf(superClass);
  }
  if (fieldsMetadata.length === 0) {
    throw new Error('!fieldsMetadata');
  }

  const mappedFieldsMetadata: FieldMetadata[] = fieldsMetadata.map((field) => ({
    ...field,
    target: PartialTypeClass,
    typeOptions: {
      ...field.typeOptions,
      nullable: true,
    },
  }));
  mappedFieldsMetadata.forEach((metadata) => getMetadataStorage().collectClassFieldMetadata(metadata));

  Object.defineProperty(PartialTypeClass, 'name', { value: `Partial${BaseClass.name}` });

  return PartialTypeClass as ConstructorType<Partial<InstanceType<TClassType>>>;
}

[korki43]

Wow. Thanks for the quick answer!