d3.selectAll(".speed") .transition("changeDownloadValue") .duration(duration / 1.125) .textTween(function({downloadSpeed}) { const that = d3.select(this), i = d3.interpolateNumber(that.text(), downloadSpeed); return t => { that.text(i(t)); }; }); d3.selectAll(".speed") .transition("changeDownloadValue") .duration(duration / 1.125) .text(0) .transition("animateNumber") .duration(duration) .delay(duration / 1.125) .text(({ downloadSpeed }) => downloadSpeed);selectAll(".speed") .transition("changeDownloadValue") .duration(duration / 1.125) .textTween(function({downloadSpeed}) { const that = d3.select(this), i = d3.interpolateNumber(that.text(), downloadSpeed); return t => { that.text(i(t)); }; }); d3.js v6