/**
 * 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.
 *
 * Default `IsNumberOptions` allow
 * `-Infinity, Infinity` but disallow `NaN`.
 *
 * @param target The value being checked.
 * @param options The optional configuration {@link IsNumberOptions}.
 * @return True if the value is a number, false otherwise.
 */
export declare function isNumber(target: any, options?: IsNumberOptions): boolean;
/**
 * Utility method for throwing an error if the {@link isNumber} test fails.
 *
 * @param target The target value being checked
 * @param field The name of the field containing the number
 * @param code Optional nervous system code
 * @param options Optional {@link IsNumberOptions} instance.
 * @throws IsError if the target is not a number
 * @returns false if an {@link IsError} is not thrown
 */
export declare function isNumberError(target: number, field: string, code?: string, options?: IsNumberOptions): boolean;