# OptionalKeysOf

`type` in `plugins` · v0.6.1

<https://docs.seedcord.org/packages/plugins/0.6.1/types/optional-keys-of>

Extract all optional keys from the given type.

This is useful when you want to create a new type that contains different type values for the optional keys only.

## Examples

```ts
import type {OptionalKeysOf, Except} from 'type-fest';

type User = {
	name: string;
	surname: string;

	luckyNumber?: number;
};

const REMOVE_FIELD = Symbol('remove field symbol');
type UpdateOperation<Entity extends object> = Except<Partial<Entity>, OptionalKeysOf<Entity>> & {
	[Key in OptionalKeysOf<Entity>]?: Entity[Key] | typeof REMOVE_FIELD;
};

const update1: UpdateOperation<User> = {
	name: 'Alice',
};

const update2: UpdateOperation<User> = {
	name: 'Bob',
	luckyNumber: REMOVE_FIELD,
};

 Utilities
```

## Declaration

```ts
type OptionalKeysOf<Type extends object> = Type extends unknown // For distributing `Type` ? (keyof { [Key in keyof Type as IsOptionalKeyOf<Type, Key> extends false ? never : Key]: never }) & keyof Type // Intersect with `keyof Type` to ensure result of `OptionalKeysOf<Type>` is always assignable to `keyof Type` : never
```