7.1 simple transitions

<!DOCTYPE html>
<meta charset="utf-8">

<link href="https://fonts.googleapis.com/css2?family=Montserrat+Alternates:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&family=Montserrat:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&family=Roboto:ital,wght@0,100;0,300;1,100;1,300&display=swap" rel="stylesheet">

<script src="https://d3js.org/d3.v3.min.js"></script>

<p id="h1">TRANSITION | SIMPLE</p>
<div id="link">by
<a href="https://slides.com/sandravizmad">SANDRA</a></div>

<style>

/*Defining text stylings*/

#h1 {
  font-size:30px;
  margin:30px 0px 0px 20px;
  color:#f5fa91;
  font-family: 'Montserrat Alternates', sans-serif;
  font-weight:300;
}

#link {
	font-family:'Montserrat Alternates', sans-serif;
  font-weight:200;
  font-size:10px;
	margin:5px 0px 0px 22px;
  color:white;
}

a:link, a:visited, a:active {
	text-decoration: none;
  color:white;
  border-bottom:1.5px dotted white;
}

body {
  background-color:#011227;
}

/*Defining chart stylings*/

circle {
  opacity:0.3;
}

</style>

//Margin conventions
var m = {top:100, right:70, bottom:50, left:40}
    w = 400 - m.left - m.right,
    h = 400 - m.top - m.bottom;

//Container
var svg = d3.select("body")
    .append("svg")
    .attr("width", w + m.left + m.right)
    .attr("height", h + m.top + m.bottom)
    .append("g")
    .attr("transform", `translate(${m.left}, ${m.top})`);

//Dataset
var data = [15, 10, 13, 19, 21, 25, 22, 18, 15, 15, 20, 18];

//X scale
var x = d3.scale.linear()
    .domain(d3.extent(data))
    .range([0, w]);

//X scale
var y = d3.scale.linear()
    .domain(d3.extent(data))
    .range([0, h - 100]);

//Draw the cricles with one transition
svg.selectAll("circle")
   .data(data)
   .enter()
   .append("circle")
   .style("fill", "#85f6fa")
   .attr("r",d => d * 0.8)
   .attr("cx",d => x(d))
   .attr("cy",d => d)
   .transition()
   .duration(6000)
   .ease("bounce")
   .style("fill", "#8ff798")
   .attr("cx",d => x(d))
   .attr("cy",d => y(d))
   .attr("r",d => d * 2);

</script>
 </body>
 </html>

https://d3js.org/d3.v3.min.js