Overview
Volatility can be calculated using the Volatility library.Straight Vol
code that uses a straight calculation of variance as the measure of volatiity.
let vl = await import('/lib/time-series/volatility/v1.0.0/volatility.mjs');
let data = [{"return":0.01},{"return":-0.01},{"return":0.002},{"return":0.013},{"return":0.007},{"return":-0.017},{"return":-0.01},];
let size = 3;
let data2 = vl.volatility(data.map(p=>p.return), size);
EWMA Vol
The following calculates an ewma of the volatility of a price series.
let vl = await import('/lib/time-series/volatility/v1.0.0/volatility.mjs');
let data = [{"return":0.01},{"return":-0.01},{"return":0.002},{"return":0.013},{"return":0.007},{"return":-0.017},{"return":-0.01},];
let alpha = 0.94;
let vol = vl.ewmaVolatility(data.map(p=>p.return), alpha);