import { Result } from "../types";
/**
 * IsNumberOptions.
 */
export interface IsNumberOptions {
    allowNaN?: boolean;
    allowInfinity?: boolean;
}
/**
 * Default options for IsNumber
 */
export declare const IS_NUMBER_OPTIONS_DEFAULTS: IsNumberOptions;
/**
 * Check if a given value is a number.
 *
 * ### Example
 * ```
 * expect(isNumber(33.33).value).toBeTruthy()
 * ```
 *
 * Default `IsNumberOptions` allow
 * `-Infinity, Infinity` but disallow `NaN`.
 *
 * @param target The value being checked.
 * @param options The optional configuration {@link IsNumberOptions}.
 */
export declare function isNumber(target: any, options?: IsNumberOptions): Result<boolean | undefined>;