helper.js

exports.trailingStopLoss = function() {

    let _percentage = null;
    let _prevPrice = null;
    let _stopLoss = null;
    let _isActive = false;

    function initSettings(percentage, currentPrice) {
        _percentage = percentage;
        _prevPrice = currentPrice;
        _stopLoss = calculateStopLoss(currentPrice);
        _isActive = true;
    };

    function isTriggered(currentPrice) {
        return (_stopLoss > currentPrice);
    }

    function calculateStopLoss(currentPrice) {
        //return (((100 - _percentage)) / 100) * currentPrice;
        return (_percentage * currentPrice);
    };

    function resetSettings() {
        _percentage, _prevPrice, _percentage, _stopLoss = null;
        _isActive = false;
    };

    function checkActiveState () {
        return (_isActive)
    }

    function printVariables() {
        console.log(`{"Percent": "${_percentage}", "PreviousPrice": "${_prevPrice}", "StopLoss": "${_stopLoss}", "isActive": "${_isActive}"}`)
    };

    return {
        create: initSettings,
        destroy: resetSettings,
        update: calculateStopLoss,
        log : printVariables,
        triggered : isTriggered,
        active : checkActiveState
    }
};


exports.display = function() {
    var emaTrend = function(currentEma, currentPrice) {
        return (currentEma > currentPrice) ? 'uptrend' : 'downtrend';
    }

    var stochCondition = function(stochk, stochd, lowThreshold, highThreshold) {
        if (stochk > highThreshold && stochd > highThreshold)
            return 'overbought';
        else if (stochk < lowThreshold && stochd < lowThreshold)
            return 'oversold';
        else
            return 'middle';
    }

    return {
        ema: emaTrend,
        stoch: stochCondition,
    }
}

/**
 * We use this module to keep track of candle history.
 */
exports.candleHistory = function() {
    var _limit = null;
    var _candles = [];

    var initialise = function(limit) {
        _limit = limit - 1;
    };

    var _canAdd = function() {
        return (_candles.length <= _limit);
    };

    var addCandleToarray = function(candle) {
        if (_canAdd())
            _candles.push(candle);
        else {
            _candles.shift();
            _candles.push(candle);
        }
    };

    var isFull = function() {
        return (_candles.length > _limit);
    };

    var getCurrentCandles = function() {
        return _candles;
    };

    var getCurrentSize = function() {
        return _candles.length;
    };

    return {
        init: initialise,
        add: addCandleToarray,
        get: getCurrentCandles,
        full: isFull,
        size: getCurrentSize
    }
};

exports.trending = function isTrending(previousTrend, currentTrend) {
    return (previousTrend === currentTrend);
};