Add a way to programmatically check if a field is nullable

[wilker7ribeiro]

Problem

I want to programmatically check if a field is nullable or not.

I want to integrate a third party filter with a query using an dynamic order by, something like:

private prepareOrderBy(filter: ThirdPartyFilter): Prisma.MyEntityOrderByWithRelationInput {
  if (filter.sortBy) {
    return filter.sortBy.reduce((orderByAcm, sortByField) => {
      orderByAcm[sortByField.field] = {
        sort: sortByField.desc ? Prisma.SortOrder.desc : Prisma.SortOrder.asc,
        nulls: sortByField.nullsLast ? Prisma.NullsOrder.last : Prisma.NullsOrder.first,
      };
      return orderByAcm;
    }, {} as Prisma.MyEntityOrderByWithRelationInput);
  }
  return { createdAt: Prisma.SortOrder.desc };
}

The problem is that the order by typing depends if the field is nullable or not (so that we can include de null last or first thing):

export type MyEntityOrderByWithRelationInput = {
  nonNullableField?: SortOrder
  nullableField?: SortOrderInput | SortOrder
}

And there is no way to know if the field is nullable or not programmatically, so I cant make it 100% dynamic.

Suggested solution

Maybe add on the FieldRef interface a field to check if the field is required:

/**
 * A reference to a specific field of a specific model
 */
export declare interface FieldRef<Model, FieldType> {
    readonly modelName: Model;
    readonly name: string;
    readonly typeName: FieldType;
    readonly isList: boolean;
    readonly isNullable: boolean; // <-- new field
}

That way I could check with prismaClient.myEntity.fields[sortByField.field].isNullable