@neabyte/chart-to-image/dist/utils/utils.js

Convert trading charts to images using Node.js canvas with advanced features: 6 chart types, VWAP/EMA/SMA indicators, custom colors, themes, hide elements, scaling, and PNG/JPEG export formats.

export function formatTimestamp(timestamp) {
    const date = new Date(timestamp);
    const now = new Date();
    const isToday = date.toDateString() === now.toDateString();
    if (isToday) {
        return date.toLocaleTimeString('en-US', {
            hour: '2-digit',
            minute: '2-digit',
            hour12: false
        });
    }
    else {
        return date.toLocaleDateString('en-US', {
            month: 'short',
            day: 'numeric',
            hour: '2-digit',
            minute: '2-digit',
            hour12: false
        });
    }
}
export function calculatePercentageChange(current, previous) {
    if (previous === 0)
        return 0;
    return ((current - previous) / previous) * 100;
}
export function calculateMovingAverage(data, period) {
    if (data.length < period)
        return [];
    const result = [];
    for (let i = period - 1; i < data.length; i++) {
        const sum = data.slice(i - period + 1, i + 1).reduce((a, b) => a + b, 0);
        result.push(sum / period);
    }
    return result;
}
export function calculateRSI(data, period = 14) {
    if (data.length < period + 1)
        return [];
    const rsiValues = [];
    for (let i = period; i < data.length; i++) {
        const rsi = calculateRSIForPeriod(data, i, period);
        rsiValues.push(rsi);
    }
    return rsiValues;
}
function calculateRSIForPeriod(data, index, period) {
    let gains = 0;
    let losses = 0;
    for (let i = index - period + 1; i <= index; i++) {
        const change = data[i] - data[i - 1];
        if (change > 0) {
            gains += change;
        }
        else {
            losses -= change;
        }
    }
    const avgGain = gains / period;
    const avgLoss = losses / period;
    if (avgLoss === 0)
        return 100;
    const rs = avgGain / avgLoss;
    return 100 - 100 / (1 + rs);
}
export function validateChartData(data) {
    if (!Array.isArray(data) || data.length === 0)
        return false;
    return data.every(item => {
        return (typeof item.timestamp === 'number' &&
            typeof item.open === 'number' &&
            typeof item.high === 'number' &&
            typeof item.low === 'number' &&
            typeof item.close === 'number' &&
            item.high >= Math.max(item.open, item.close) &&
            item.low <= Math.min(item.open, item.close) &&
            item.timestamp > 0);
    });
}
export function sortChartData(data) {
    return [...data].sort((a, b) => a.timestamp - b.timestamp);
}
export function filterChartDataByDate(data, startDate, endDate) {
    const startTimestamp = startDate.getTime();
    const endTimestamp = endDate.getTime();
    return data.filter(item => {
        return item.timestamp >= startTimestamp && item.timestamp <= endTimestamp;
    });
}
export function timeframeToMs(timeframe) {
    const value = parseInt(timeframe.slice(0, -1));
    const unit = timeframe.slice(-1);
    switch (unit) {
        case 'm':
            return value * 60 * 1000;
        case 'h':
            return value * 60 * 60 * 1000;
        case 'd':
            return value * 24 * 60 * 60 * 1000;
        case 'w':
            return value * 7 * 24 * 60 * 60 * 1000;
        default:
            throw new Error(`Unsupported timeframe unit: ${unit}`);
    }
}
export function getPriceChangeColor(current, previous) {
    if (current > previous)
        return '#26a69a';
    if (current < previous)
        return '#ef5350';
    return '#424242';
}
export function formatPrice(price, decimals = 2) {
    return price.toFixed(decimals);
}
export function calculateVWAP(data) {
    if (data.length === 0)
        return 0;
    let totalVolume = 0;
    let totalVolumePrice = 0;
    data.forEach(item => {
        const volume = item.volume || 0;
        const typicalPrice = (item.high + item.low + item.close) / 3;
        totalVolume += volume;
        totalVolumePrice += volume * typicalPrice;
    });
    return totalVolume > 0 ? totalVolumePrice / totalVolume : 0;
}