/**
 * Supertrend indicator.
 * Returns `[supertrend, finalUpper, finalLower, isUpMask]`.
 * `supertrend` contains the plotted trend line (either finalLower when up or finalUpper when down),
 * `finalUpper`/`finalLower` are the band values, and `isUpMask` is a Uint8Array mask (1 when up).
 * NaNs are preserved for invalid inputs or before enough data is available.
 * @param high High price series
 * @param low Low price series
 * @param close Close price series
 * @param period ATR lookback period
 * @param mult Multiplier applied to ATR to form bands
 * @returns Tuple `[supertrend, finalUpper, finalLower, isUpMask]`
 */
export declare function supertrend(high: ArrayLike<number>, low: ArrayLike<number>, close: ArrayLike<number>, period: number, mult: number): [Float64Array, Float64Array, Float64Array, Uint8Array];