/**
* Force Index Indicator
* Measures the force of bulls vs bears by combining price change and volume
*/
import { calculateEMA } from './moving-averages'
export interface ForceIndexData {
forceIndex: number | null
smoothedForceIndex: number | null
signal: 'bullish' | 'bearish' | 'neutral' | null
strength: 'weak' | 'moderate' | 'strong' | null
}
export function calculateForceIndex(
closes: number[],
volumes: number[],
smoothingPeriod: number = 13
): ForceIndexData {
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: number[] = []
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: number | null = 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: 'bullish' | 'bearish' | 'neutral' | null = null
if (currentForceIndex > 0) signal = 'bullish'
else if (currentForceIndex < 0) signal = 'bearish'
else signal = 'neutral'
// Determine strength based on magnitude
let strength: 'weak' | 'moderate' | 'strong' | null = 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,
}
}
