constructor (parent, chartGroup) {
        super();

        this._g = undefined;

        this._labelOffsetX = 10;
        this._labelOffsetY = 15;
        this._hasLabelOffsetY = false;
        this._dyOffset = '0.35em'; // this helps center labels https://github.com/d3/d3-3.x-api-reference/blob/master/SVG-Shapes.md#svg_text
        this._titleLabelOffsetX = 2;

        this._gap = 5;

        this._fixedBarHeight = false;
        this._rowCssClass = 'row';
        this._titleRowCssClass = 'titlerow';
        this._renderTitleLabel = false;

        this._x = undefined;

        this._elasticX = undefined;

        this._xAxis = axisBottom();

        this._rowData = undefined;

        this.rowsCap = this.cap;

        this.title(d => `${this.cappedKeyAccessor(d)}: ${this.cappedValueAccessor(d)}`);

        this.label(d => this.cappedKeyAccessor(d));

        this.anchor(parent, chartGroup);
    }
Create a Row Chart.
@example
// create a row chart under #chart-container1 element using the default global chart group
var chart1 = new RowChart('#chart-container1');
// create a row chart under #chart-container2 element using chart group A
var chart2 = new RowChart('#chart-container2', 'chartGroupA');
@param {String|node|d3.selection} parent - Any valid
{@link https://github.com/d3/d3-selection/blob/master/README.md#select d3 single selector} specifying
a dom block element such as a div; or a dom element or d3 selection.
@param {String} [chartGroup] - The name of the chart group this chart instance should be placed in.
Interaction with a chart will only trigger events and redraws within the chart's group.