code: function updateLegendGroup(selection, viewBox, orient) {
    const widthFactor = 0.2;
    const scaleF = viewBox.right * widthFactor / 120;
    const o = orient.split('-');
    const viewW = viewBox.right;
    const viewH = viewBox.bottom;
    const legW = viewW * widthFactor;
    const legH = legW * 50 / 120;
    const posX = {left: legW / 10, right: viewW - legW - (legW / 10)}[o[1]];
    const posY = {top: legH / 10, bottom: viewH - legH - (legH / 10)}[o[0]];
    selection.attr('transform',
                   `translate(${posX}, ${posY}) scale(${scaleF})`);
  }
docs: Legend group component
  @param {d3.selection} selection - selection of group container (svg:g)