/**
* Hull Moving Average (HMA) Indicator
* Moving average designed to reduce lag while maintaining smoothness
*/
import { calculateWMA } from './wma';
export function calculateHMA(closes, period = 16) {
if (closes.length < period || period < 2)
return [];
const hma = [];
const halfPeriod = Math.floor(period / 2);
const sqrtPeriod = Math.floor(Math.sqrt(period));
// Need enough data for the longest WMA (period)
const requiredLength = period + sqrtPeriod - 1;
if (closes.length < requiredLength)
return [];
for (let i = requiredLength - 1; i < closes.length; i++) {
// Step 1: Calculate WMA for half period, multiplied by 2
const wmaHalf = calculateWMA(closes.slice(i - halfPeriod - sqrtPeriod + 1, i - sqrtPeriod + 1), halfPeriod);
const wmaHalfValue = wmaHalf.length > 0 ? wmaHalf[wmaHalf.length - 1] * 2 : 0;
// Step 2: Calculate WMA for full period
const wmaFull = calculateWMA(closes.slice(i - period - sqrtPeriod + 1, i - sqrtPeriod + 1), period);
const wmaFullValue = wmaFull.length > 0 ? wmaFull[wmaFull.length - 1] : 0;
// Step 3: Calculate Raw HMA
const rawHMA = wmaHalfValue - wmaFullValue;
// Step 4: Calculate final HMA using WMA of Raw HMA
const rawHMAData = [rawHMA]; // Start with current rawHMA
// Build historical Raw HMA data for sqrtPeriod WMA calculation
for (let j = 1; j < sqrtPeriod; j++) {
const idx = i - j;
if (idx >= 0) {
const prevWmaHalf = calculateWMA(closes.slice(idx - halfPeriod - sqrtPeriod + 1, idx - sqrtPeriod + 1), halfPeriod);
const prevWmaHalfValue = prevWmaHalf.length > 0 ? prevWmaHalf[prevWmaHalf.length - 1] * 2 : 0;
const prevWmaFull = calculateWMA(closes.slice(idx - period - sqrtPeriod + 1, idx - sqrtPeriod + 1), period);
const prevWmaFullValue = prevWmaFull.length > 0 ? prevWmaFull[prevWmaFull.length - 1] : 0;
rawHMAData.unshift(prevWmaHalfValue - prevWmaFullValue);
}
}
// Calculate final HMA as WMA of Raw HMA data
const finalHMA = calculateWMA(rawHMAData, sqrtPeriod);
if (finalHMA.length > 0) {
hma.push(finalHMA[finalHMA.length - 1]);
}
}
return hma;
}
