// Licensed under the Apache License, Version 2.0
// © mihakralj
//@version=6
indicator("On Balance Volume (OBV)", "OBV", overlay=false)

//@function Calculates On Balance Volume
//@param c Close price series
//@param vol Volume series
//@returns Cumulative On Balance Volume value
//@optimized for performance and dirty data
obv(series float c = close, series float vol = volume) =>
    float close_price = nz(c, close)
    float volume_val = nz(vol, 0.0)
    float prev_close = nz(close_price[1], close_price)
    var float obv_cumulative = 0.0
    obv_cumulative += close_price > prev_close ? volume_val : close_price < prev_close ? -volume_val : 0.0
    obv_cumulative

// ---------- Main loop ----------

// Calculation
obv_value = obv(close, volume)

// Plot
plot(obv_value, "OBV", color=color.yellow, linewidth=2)