Sankey column pre-sort

<!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>
    
    function constant(x) {
      return function(d) {
        return d[x];
      };
    }
    
    function getNodeSort (node, id) {
      return id(node)
    }
    
    //////////////////////////////////////////////////////
        
    let nodes = [
      {"id": 1, "c": 0, "d": "A"},
      {"id": 2, "c": 1, "d": "A"},
      {"id": 3, "c": 1, "d": "E"},
      {"id": 4, "c": 3, "d": "AA"},
      {"id": 5, "c": 4, "d": "A"}
    ]
    
    /*let s = function(node) {
      // return node.c
      // return node.d
      // return 1
      return node.c < 2 ? 0 : 1
    }*/
    
    let s = "d"
    
    //////////////////////////////////////////////////////
        
    let sortNodes = typeof s === 'function' ? s : constant(s)
    
    //////////////////////////////////////////////////////
    
    let columnSet = new Set()
    let columnArray = []

nodes.forEach(function(node) {
      columnSet.add(getNodeSort(node, sortNodes))
    })
    
    console.log("------------------------------------------")
    console.log(columnSet)

columnArray = [...columnSet].sort()
    
    nodes.forEach(function(node) {
      node.column1 = columnArray.indexOf(getNodeSort(node, sortNodes))
    })
    
   	//////////////////////////////////////////////////////
    
    console.log(columnArray)
    console.log(nodes)
    console.log("------------------------------------------")

</script>
</body>

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