/**
* Volume Rate of Change (ROC) Indicator
* Measures the percentage change in volume over a specified period
*/
/**
* Calculate Volume Rate of Change
* @param volumes Array of volume data
* @param period Period for ROC calculation (default 12)
* @returns VolumeROCData object
*/
export function calculateVolumeROC(volumes, period = 12) {
// Minimum 3 data points required
if (volumes.length < 3) {
return null;
}
// Use adaptive period
const effectivePeriod = Math.min(period, volumes.length - 1);
const currentVolume = volumes[volumes.length - 1];
const previousVolume = volumes[volumes.length - 1 - effectivePeriod];
// Calculate ROC: ((Current - Previous) / Previous) * 100
const roc = previousVolume > 0 ? ((currentVolume - previousVolume) / previousVolume) * 100 : 0;
// Determine trend
let trend = 'stable';
if (roc > 10) {
trend = 'increasing';
}
else if (roc < -10) {
trend = 'decreasing';
}
// Calculate signal strength based on ROC magnitude
const strength = Math.min(100, Math.abs(roc) * 2);
// Check overbought/oversold levels
const overbought = roc > 50;
const oversold = roc < -50;
// Check for zero line crossovers
let bullishSignal = false;
let bearishSignal = false;
if (volumes.length >= period + 2) {
const prevROC = calculateVolumeROC(volumes.slice(0, -1), period);
if (prevROC) {
if (roc > 0 && prevROC.roc <= 0) {
bullishSignal = true;
}
else if (roc < 0 && prevROC.roc >= 0) {
bearishSignal = true;
}
}
}
// Generate trading signal
let signal = 'neutral';
if (bullishSignal && !overbought) {
signal = 'buy';
}
else if (bearishSignal && !oversold) {
signal = 'sell';
}
else if (overbought) {
signal = 'sell';
}
else if (oversold) {
signal = 'buy';
}
// Determine momentum
let momentum = 'weak';
const absROC = Math.abs(roc);
if (absROC > 100) {
momentum = 'strong';
}
else if (absROC > 25) {
momentum = 'moderate';
}
return {
roc,
currentVolume,
previousVolume,
period,
trend,
strength,
overbought,
oversold,
bullishSignal,
bearishSignal,
signal,
momentum
};
}
/**
* Calculate Volume ROC for multiple periods
* @param volumes Array of volume data
* @param periods Array of periods to calculate ROC for
* @returns Array of VolumeROCData objects
*/
export function calculateMultipleVolumeROC(volumes, periods = [12, 25, 50]) {
return periods
.map(period => calculateVolumeROC(volumes, period))
.filter((roc) => roc !== null);
}
/**
* Get Volume ROC interpretation
* @param roc VolumeROCData object
* @returns Human-readable interpretation
*/
export function getVolumeROCInterpretation(roc) {
const { roc: value, trend, overbought, oversold, bullishSignal, bearishSignal, momentum } = roc;
let interpretation = `Volume ROC (${roc.period}): ${value.toFixed(2)}%`;
if (bullishSignal) {
interpretation += ' - Bullish zero line crossover';
}
else if (bearishSignal) {
interpretation += ' - Bearish zero line crossover';
}
else if (overbought) {
interpretation += ' - Volume overbought';
}
else if (oversold) {
interpretation += ' - Volume oversold';
}
else {
interpretation += ` - ${trend} volume trend`;
}
interpretation += ` (${momentum} momentum)`;
return interpretation;
}
/**
* Calculate volume acceleration
* @param roc VolumeROCData object
* @param volumes Array of volume data
* @returns Volume acceleration analysis
*/
export function calculateVolumeAcceleration(roc, volumes) {
if (volumes.length < roc.period * 2) {
return { acceleration: 0, interpretation: 'Insufficient data', signal: 'stable' };
}
// Calculate ROC of ROC (acceleration)
const recentROC = calculateVolumeROC(volumes.slice(-roc.period * 2), roc.period);
const olderROC = calculateVolumeROC(volumes.slice(-roc.period * 3, -roc.period), roc.period);
if (!recentROC || !olderROC) {
return { acceleration: 0, interpretation: 'Insufficient data', signal: 'stable' };
}
const acceleration = recentROC.roc - olderROC.roc;
let signal = 'stable';
let interpretation;
if (acceleration > 10) {
signal = 'accelerating';
interpretation = 'Volume is accelerating - strong momentum building';
}
else if (acceleration < -10) {
signal = 'decelerating';
interpretation = 'Volume is decelerating - momentum weakening';
}
else {
signal = 'stable';
interpretation = 'Volume momentum is stable';
}
return { acceleration, interpretation, signal };
}
/**
* Analyze volume trend consistency
* @param volumes Array of volume data
* @param periods Number of periods to analyze
* @returns Volume trend analysis
*/
export function analyzeVolumeTrendConsistency(volumes, periods = 20) {
if (volumes.length < periods + 12) {
return { overallTrend: 'stable', trendStrength: 0, consistencyScore: 0, dominantPeriod: 12 };
}
const rocData = calculateMultipleVolumeROC(volumes, [12, 25, 50]);
if (rocData.length === 0) {
return { overallTrend: 'stable', trendStrength: 0, consistencyScore: 0, dominantPeriod: 12 };
}
// Analyze trend consistency across different periods
let increasingCount = 0;
let decreasingCount = 0;
let totalStrength = 0;
let dominantPeriod = 12;
let maxStrength = 0;
for (const roc of rocData) {
if (roc.trend === 'increasing')
increasingCount++;
if (roc.trend === 'decreasing')
decreasingCount++;
totalStrength += roc.strength;
if (roc.strength > maxStrength) {
maxStrength = roc.strength;
dominantPeriod = roc.period;
}
}
const overallTrend = increasingCount > decreasingCount ? 'increasing' :
decreasingCount > increasingCount ? 'decreasing' : 'stable';
const trendStrength = totalStrength / rocData.length;
const consistencyScore = Math.max(increasingCount, decreasingCount) / rocData.length * 100;
return { overallTrend, trendStrength, consistencyScore, dominantPeriod };
}
