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react-querybuilder

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React Query Builder component for constructing queries and filters, with utilities for executing them in various database and evaluation contexts

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/** 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;