/**
* ZigZag Indicator
* Filters out market noise and shows major price swings
*/
export interface ZigZagData {
zigzag: number | null // Current ZigZag value
direction: 'up' | 'down' | 'sideways' | null
swingPoints: Array<{ index: number; value: number; type: 'high' | 'low' }>
lastSwing: { index: number; value: number; type: 'high' | 'low' } | null
}
export function calculateZigZag(
closes: number[],
deviation: number = 5 // Minimum deviation in percentage
): ZigZagData {
if (closes.length < 3) {
return {
zigzag: null,
direction: null,
swingPoints: [],
lastSwing: null,
}
}
const swingPoints: Array<{ index: number; value: number; type: 'high' | 'low' }> = []
let lastSwing: { index: number; value: number; type: 'high' | 'low' } | null = null
let trend: 'up' | 'down' = 'up' // Start assuming uptrend
// First, find initial swing point
let maxValue = closes[0]
let minValue = closes[0]
let maxValueIndex = 0
let minValueIndex = 0
for (let i = 1; i < closes.length; i++) {
if (closes[i] > maxValue) {
maxValue = closes[i]
maxValueIndex = i
}
if (closes[i] < minValue) {
minValue = closes[i]
minValueIndex = i
}
}
// Start with the first significant move
if (maxValueIndex < minValueIndex) {
// Started with up move
swingPoints.push({ index: 0, value: closes[0], type: 'low' })
lastSwing = { index: maxValueIndex, value: maxValue, type: 'high' }
swingPoints.push(lastSwing)
trend = 'down'
} else {
// Started with down move
swingPoints.push({ index: 0, value: closes[0], type: 'high' })
lastSwing = { index: minValueIndex, value: minValue, type: 'low' }
swingPoints.push(lastSwing)
trend = 'up'
}
// Process remaining data
for (let i = lastSwing.index + 1; i < closes.length; i++) {
const currentValue = closes[i]
if (trend === 'down') {
// Looking for lower low
if (currentValue < lastSwing.value * (1 - deviation / 100)) {
// Found new swing low
lastSwing = { index: i, value: currentValue, type: 'low' }
swingPoints.push(lastSwing)
trend = 'up'
} else if (currentValue > lastSwing.value) {
// Price moved up significantly, update swing point
lastSwing = { index: i, value: currentValue, type: 'high' }
swingPoints[swingPoints.length - 1] = lastSwing
}
} else {
// Looking for higher high
if (currentValue > lastSwing.value * (1 + deviation / 100)) {
// Found new swing high
lastSwing = { index: i, value: currentValue, type: 'high' }
swingPoints.push(lastSwing)
trend = 'down'
} else if (currentValue < lastSwing.value) {
// Price moved down significantly, update swing point
lastSwing = { index: i, value: currentValue, type: 'low' }
swingPoints[swingPoints.length - 1] = lastSwing
}
}
}
// Determine current direction
let direction: 'up' | 'down' | 'sideways' | null = null
if (swingPoints.length >= 2) {
const lastTwo = swingPoints.slice(-2)
if (lastTwo[1].type === 'high' && lastTwo[1].value > lastTwo[0].value) {
direction = 'up'
} else if (lastTwo[1].type === 'low' && lastTwo[1].value < lastTwo[0].value) {
direction = 'down'
} else {
direction = 'sideways'
}
}
return {
zigzag: lastSwing ? lastSwing.value : null,
direction,
swingPoints,
lastSwing,
}
}
