transition grouped <-> stacked

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>

<body>
  <script>
var n = 10, // number of samples
    m = 5; // number of series

var data = d3.range(m).map(function() { 
  return d3.range(n).map(Math.random); 
});

var margin = {top: 20, right: 30, bottom: 30, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var y = d3.scaleLinear()
    .domain([0, n])
    .rangeRound([height, 0])
		.nice();
    
var yMax = d3.max(data, function(d) { return d3.max(d); });

var x = d3.scaleBand()
    .rangeRound([0, width])
    .paddingInner(0.05)
    .align(0.1)
    .domain(d3.range(n));
    
var x1 = d3.scaleBand()
    .domain(d3.range(m))
    .range([0, x.bandwidth() - 10]);

var z = d3.scaleOrdinal()
    .range(["#98abc5", "#8a89a6", "#7b6888", "#6b486b", "#a05d56", "#d0743c", "#ff8c00"]);

var ChartType = 'stacked';     
    
var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.selectAll("body").on("click",function(){
    if(ChartType==="stacked"){ChartType = "grouped",DessinerGraphique(data,ChartType);}
    else{ChartType="stacked",DessinerGraphique(data,ChartType);}
      
  });
 
 
svg.append("g").selectAll("g")
    .data(data)
  .enter().append("g")
    .style("fill", function(d, i) { return z(i); })
    .attr("transform", function(d, i) { return "translate(" + x1(i) + ",0)"; })
  .selectAll("rect")
    .data(function(d) { return d; })
  .enter().append("rect")
    .attr("width", x1.bandwidth())
    .attr("height", y)
    .attr("x", function(d, i) { return x(i); })
    .attr("y", function(d) { return height - y(d); });

function DessinerGraphique(data,type){  
if (type==="stacked"){  
  		console.log("stacké")
  		
   y.domain([0, n]);
  
}
if (type==="grouped"){
  
  y.domain([0, yMax]);

svg.selectAll('rect').data(data)
  		.transition()
      .duration(500)
      .delay(function(d, i) { return i * 10; })
      .attr("x", function(d, i) { return x(i) + x.bandwidth() / n * this.parentNode.__data__.key; })
      .attr("width", x.bandwidth() / n)
    .transition()
      .attr("y", function(d) { return y(d[1] - d[0]); })
      .attr("height", function(d) { return y(0) - y(d[1] - d[0]); });
  
  		console.log("groupé")
  		  
}
}
    
  </script>
</body>

https://d3js.org/d3.v4.min.js