Using d3.transition.

d3-transition.js

const markers = d3.selectAll(‘.marker’)
                  .data(data, d => d.id)
                  .enter()
                  .append(‘circle’)
                  .attr(‘class’, ‘marker’)
                  .attr(‘r’, 7.5)
                  .transition()
                  .duration(1000)
                  .attr(‘cx’, d => d.x)
                  .attr(‘cy’, d => d.y);