understanding-sampling/src/js/d3/init-countertext.js

export default (selection, options) => {
  // counter text
  selection.append('text')
    .attr('x', options.width * 0.65)
    .attr('y', options.height / 2.3)
    .attr('class', 'counter')
    .text('0')
    .attr('fill', options.baseColor)
    .attr('fill-opacity', 1)
    .style('font-size', 64)
    .style('visibility', 'hidden');
};