react-querybuilder
Version:
React Query Builder component for constructing queries and filters, with utilities for executing them in various database and evaluation contexts
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text/typescript
/**
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.
@example
```
import type {OptionalKeysOf, Except} from 'type-fest';
interface 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
};
```
@group type-fest
*/
export type OptionalKeysOf<BaseType extends object> = BaseType extends unknown ? (keyof { [Key in keyof BaseType as BaseType extends Record<Key, BaseType[Key]> ? never : Key] : never }) & (keyof BaseType) : never;