import { MessageFunctionType, Result } from '../types';
export interface IsNegativeErrors {
    TARGET_ARGUMENT_NOT_A_NUMBER: MessageFunctionType;
}
export declare const IS_NEGATIVE_ERRORS: IsNegativeErrors;
/**
 * Tests if the value is a negative number.
 *
 * ### Example
 * ```
 * expect(isNegative(-1).value).toBeTruthy()
 * ```
 * @param target The value being checked.
 */
export declare function isNegative(target: number): Result<boolean | undefined>;