/**
 * Check if the value is an object.
 */
export declare const isObject: (value: unknown) => boolean;
/**
 * Check if the value is a symbol.
 */
export declare const isSymbol: (value: unknown) => boolean;
/**
 * Check if the value is a function.
 */
export declare const isFunction: (value: unknown) => boolean;
/**
 * For each the collection.
 */
export declare const each: <T>(collection: T | T[] | null | undefined, iterator: (item: T, i: string | number | symbol, collection: T | T[] | null | undefined) => void) => void;
/**
 * Reduce the collection to a single value.
 */
export declare const reduce: <T, TResult>(collection: T | T[] | null | undefined, iterator: (carry: TResult, item: T, i: string | number | symbol, collection: T | T[] | null | undefined) => TResult, carry: TResult) => TResult;
/**
 * Invert the keys and values of an object.
 */
export declare const invert: <T = any>(obj: T, multiValue?: boolean) => T;