code: function verticalBarsTween(d) {
              let node = d3Selection.select(this),
                  i = d3Interpolate.interpolateRound(0, chartHeight - yScale(getValue(d))),
                  y = d3Interpolate.interpolateRound(chartHeight, yScale(getValue(d))),
                  j = d3Interpolate.interpolateNumber(0, 1);
  
              return function (t) {
                  node.attr('y', y(t))
                      .attr('height', i(t)).style('opacity', j(t));
              }
          }
docs: Animation tween of vertical bars
  @param  {obj} d data of bar
  @return {void}