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ts-toolbelt

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TypeScript's largest utility library

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/** * @hidden */ export declare type _UndefinableKeys<O extends object> = { [K in keyof O]-?: [O[K] & (undefined)] extends [never] ? never : K; }[keyof O]; /** * Get the keys of `O` that are `undefined` * (⚠️ needs `--strictNullChecks` enabled) * @param O * @returns [[Key]] * @example * ```ts * ``` */ export declare type UndefinableKeys<O extends object> = O extends unknown ? _UndefinableKeys<O> : never;