/**
* Force Index Indicator
* Measures the force of bulls vs bears by combining price change and volume
*/
import { calculateEMA } from './moving-averages';
export function calculateForceIndex(closes, volumes, smoothingPeriod = 13) {
if (closes.length < 2 || volumes.length < 2) {
return {
forceIndex: null,
smoothedForceIndex: null,
signal: null,
strength: null,
};
}
// Calculate raw Force Index: (Close - Close_prev) * Volume
const rawForceIndex = [];
for (let i = 1; i < closes.length; i++) {
const priceChange = closes[i] - closes[i - 1];
const volume = volumes[i] || 0;
const forceIndexValue = priceChange * volume;
rawForceIndex.push(forceIndexValue);
}
if (rawForceIndex.length === 0) {
return {
forceIndex: null,
smoothedForceIndex: null,
signal: null,
strength: null,
};
}
// Get current raw Force Index
const currentForceIndex = rawForceIndex[rawForceIndex.length - 1];
// Calculate smoothed Force Index using EMA
let currentSmoothedForceIndex = null;
if (rawForceIndex.length >= smoothingPeriod) {
const smoothedValues = calculateEMA(rawForceIndex, smoothingPeriod);
if (smoothedValues.length > 0) {
currentSmoothedForceIndex = smoothedValues[smoothedValues.length - 1];
}
}
// Determine signal based on Force Index direction
let signal = null;
if (currentForceIndex > 0)
signal = 'bullish';
else if (currentForceIndex < 0)
signal = 'bearish';
else
signal = 'neutral';
// Determine strength based on magnitude
let strength = null;
const absForceIndex = Math.abs(currentForceIndex);
// These thresholds would need to be calibrated based on the asset and timeframe
if (absForceIndex > 1000000)
strength = 'strong'; // Very large volume * price change
else if (absForceIndex > 100000)
strength = 'moderate';
else
strength = 'weak';
return {
forceIndex: currentForceIndex,
smoothedForceIndex: currentSmoothedForceIndex,
signal,
strength,
};
}
