ema.src.js 6.39 KB
/**
 * @license Highstock JS v7.2.0 (2019-09-03)
 *
 * Indicator series type for Highstock
 *
 * (c) 2010-2019 Sebastian Bochan
 *
 * License: www.highcharts.com/license
 */
'use strict';
(function (factory) {
    if (typeof module === 'object' && module.exports) {
        factory['default'] = factory;
        module.exports = factory;
    } else if (typeof define === 'function' && define.amd) {
        define('highcharts/indicators/ema', ['highcharts', 'highcharts/modules/stock'], function (Highcharts) {
            factory(Highcharts);
            factory.Highcharts = Highcharts;
            return factory;
        });
    } else {
        factory(typeof Highcharts !== 'undefined' ? Highcharts : undefined);
    }
}(function (Highcharts) {
    var _modules = Highcharts ? Highcharts._modules : {};
    function _registerModule(obj, path, args, fn) {
        if (!obj.hasOwnProperty(path)) {
            obj[path] = fn.apply(null, args);
        }
    }
    _registerModule(_modules, 'indicators/ema.src.js', [_modules['parts/Globals.js'], _modules['parts/Utilities.js']], function (H, U) {
        /* *
         *
         *  License: www.highcharts.com/license
         *
         * */



        var isArray = U.isArray;

        var seriesType = H.seriesType,
            correctFloat = H.correctFloat;

        /**
         * The EMA series type.
         *
         * @private
         * @class
         * @name Highcharts.seriesTypes.ema
         *
         * @augments Highcharts.Series
         */
        seriesType(
            'ema',
            'sma',
            /**
             * Exponential moving average indicator (EMA). This series requires the
             * `linkedTo` option to be set.
             *
             * @sample stock/indicators/ema
             *         Exponential moving average indicator
             *
             * @extends      plotOptions.sma
             * @since        6.0.0
             * @product      highstock
             * @optionparent plotOptions.ema
             */
            {
                params: {
                    /**
                     * The point index which indicator calculations will base. For
                     * example using OHLC data, index=2 means the indicator will be
                     * calculated using Low values.
                     *
                     * By default index value used to be set to 0. Since Highstock 7
                     * by default index is set to 3 which means that the ema
                     * indicator will be calculated using Close values.
                     */
                    index: 3,
                    period: 9 // @merge 14 in v6.2
                }
            },
            /**
             * @lends Highcharts.Series#
             */
            {
                accumulatePeriodPoints: function (
                    period,
                    index,
                    yVal
                ) {
                    var sum = 0,
                        i = 0,
                        y = 0;

                    while (i < period) {
                        y = index < 0 ? yVal[i] : yVal[i][index];
                        sum = sum + y;
                        i++;
                    }

                    return sum;
                },
                calculateEma: function (
                    xVal,
                    yVal,
                    i,
                    EMApercent,
                    calEMA,
                    index,
                    SMA
                ) {
                    var x = xVal[i - 1],
                        yValue = index < 0 ? yVal[i - 1] : yVal[i - 1][index],
                        y;

                    y = calEMA === undefined ?
                        SMA : correctFloat((yValue * EMApercent) +
                        (calEMA * (1 - EMApercent)));

                    return [x, y];
                },
                getValues: function (series, params) {
                    var period = params.period,
                        xVal = series.xData,
                        yVal = series.yData,
                        yValLen = yVal ? yVal.length : 0,
                        EMApercent = 2 / (period + 1),
                        sum = 0,
                        EMA = [],
                        xData = [],
                        yData = [],
                        index = -1,
                        SMA = 0,
                        calEMA,
                        EMAPoint,
                        i;

                    // Check period, if bigger than points length, skip
                    if (yValLen < period) {
                        return false;
                    }

                    // Switch index for OHLC / Candlestick / Arearange
                    if (isArray(yVal[0])) {
                        index = params.index ? params.index : 0;
                    }

                    // Accumulate first N-points
                    sum = this.accumulatePeriodPoints(
                        period,
                        index,
                        yVal
                    );

                    // first point
                    SMA = sum / period;

                    // Calculate value one-by-one for each period in visible data
                    for (i = period; i < yValLen + 1; i++) {
                        EMAPoint = this.calculateEma(
                            xVal,
                            yVal,
                            i,
                            EMApercent,
                            calEMA,
                            index,
                            SMA
                        );
                        EMA.push(EMAPoint);
                        xData.push(EMAPoint[0]);
                        yData.push(EMAPoint[1]);
                        calEMA = EMAPoint[1];
                    }

                    return {
                        values: EMA,
                        xData: xData,
                        yData: yData
                    };
                }
            }
        );

        /**
         * A `EMA` series. If the [type](#series.ema.type) option is not
         * specified, it is inherited from [chart.type](#chart.type).
         *
         * @extends   series,plotOptions.ema
         * @since     6.0.0
         * @product   highstock
         * @excluding dataParser, dataURL
         * @apioption series.ema
         */

    });
    _registerModule(_modules, 'masters/indicators/ema.src.js', [], function () {


    });
}));