NullableProps

[sheam]

Like the 'Optional' utility type, could we have the equivilant which makes fields of the object nullable instead of optional?

For example if I have the type:

interface IPerson {
  name: string;
  age: string;
}

I would like a utility type NullableFields (or whatever name) to transform it into the following:

type NullablePerson = NullableFields<IPerson>;

// resulting type is:
{
  name: string|null;
  age: number|null;
}

// OR type NullableNamePerson = NullableFields<IPerson, 'name'>;

//resulting type is:
{
  name: string|null;
  age: number;
}

Thanks.

Forgive me if this already exists under another name.

[hugo-labs-77]

It seems like you're looking for a way to transform existing types to make their fields nullable. To achieve this, you could use a mapped type approach in TypeScript. For example, you could define NullableFields like this:

type NullableFields<T> = {
  [K in keyof T]: T[K] | null;
};

This would cover the base case for all fields. For the second use case, consider adding a second type parameter that allows specifying which fields to transform, using conditional types to achieve that. Would you like suggestions on how to implement that second parameter?

[Bbk1AtJJF8]

Have you considered that your NullableFields type could also accept a second parameter to specify which properties to make nullable, similar to how you're suggesting with NullableNamePerson? This could enhance the utility and flexibility of the type.

[olga-labs-36]

Have you thought about how NullableFields could handle primitive types differently than object types, since currently it appears to assume all properties are defined and of specific types in the original interface?