/**
* Center of Gravity Indicator
* Uses physics concept to find the "center of gravity" of price action
*/
import { calculateWMA } from './wma'
export interface COGData {
cog: number | null // Center of Gravity value
signal: 'overbought' | 'oversold' | 'neutral' | null
trend: 'bullish' | 'bearish' | 'neutral' | null
}
export function calculateCOG(
closes: number[],
period: number = 10
): COGData {
// Minimum 3 data points required
if (closes.length < 3) {
return {
cog: null,
signal: null,
trend: null,
}
}
// Use adaptive period
const effectivePeriod = Math.min(period, closes.length)
// Calculate WMA for each sub-period from 1 to effectivePeriod
const wmaValues: number[] = []
for (let i = 1; i <= effectivePeriod; i++) {
const wma = calculateWMA(closes, i)
if (wma.length > 0) {
wmaValues.push(wma[wma.length - 1])
} else {
// Fallback: use simple average
const avg = closes.slice(-i).reduce((a, b) => a + b, 0) / i
wmaValues.push(avg)
}
}
if (wmaValues.length === 0) {
return {
cog: null,
signal: null,
trend: null,
}
}
// Calculate Center of Gravity: -∑(WMA(i) × i) / ∑WMA(i)
let numerator = 0
let denominator = 0
for (let i = 0; i < wmaValues.length; i++) {
const weight = i + 1 // i starts from 1 to period
numerator += wmaValues[i] * weight
denominator += wmaValues[i]
}
if (denominator === 0) {
return {
cog: null,
signal: null,
trend: null,
}
}
const cog = -numerator / denominator
// Determine signal (COG can be used as oscillator)
let signal: 'overbought' | 'oversold' | 'neutral' | null = null
const currentPrice = closes[closes.length - 1]
// Compare COG with current price (simplified signal)
const priceDiff = (currentPrice - Math.abs(cog)) / Math.abs(cog)
if (priceDiff > 0.02) signal = 'overbought' // Price significantly above COG
else if (priceDiff < -0.02) signal = 'oversold' // Price significantly below COG
else signal = 'neutral'
// Determine trend based on COG position relative to price
let trend: 'bullish' | 'bearish' | 'neutral' | null = null
if (currentPrice > Math.abs(cog)) trend = 'bullish'
else if (currentPrice < Math.abs(cog)) trend = 'bearish'
else trend = 'neutral'
return {
cog,
signal,
trend,
}
}
