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/** Checks if `value` is nullish. Literal types are narrowed accordingly. */export const nullish = <T>(value: T): value is Nullish<T> =>  value === undefined || value === null;
type Nullish<T> = PickNullish<T> extends never ? Extract<T, undefined | null>  : PickNullish<T>;
type PickNullish<T> =  | (null extends T ? null : never)  | (undefined extends T ? undefined : never);
/** * Checks if `value` is not nullish. Literal types are narrowed accordingly. * * @example * ``` * const nums = (...values: (number | undefined)[]): number[] => values.filter(notNullish) * ``` */export const notNullish = <T>(value: T | null | undefined): value is T =>  value !== null && value !== undefined;