import { either as E, readonlyNonEmptyArray as RNEA } from 'fp-ts/lib';
import { HighLowClose } from '../types.js';
/**
 * The Average True Range (ATR) a period of the True Range Indicator,
 * being the greatest out of current high minus the current low,
 * the absolute value of current high minus previous close
 * and the absolute value of the current low minus the prevous close.
 *
 * @public
 */
export declare const atr: (values: HighLowClose<number>, period?: number) => E.Either<Error, RNEA.ReadonlyNonEmptyArray<number>>;