Reg_Test

<!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>
    console.clear();
    
    var width = 960;
    var height = 500;
    var margin = {
                    top: 20,
                    right: 20,
                    bottom: 30,
                    left: 40
                };
    
    var svg = d3.select("body").append("svg")
      .attr("width", width - margin.left - margin.right)
      .attr("height", height - margin)
    
    var g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");
    
    var x0 = d3.scaleBand()
                .rangeRound([0, width])
                .paddingInner(0.1);

var x1 = d3.scaleBand()
                .padding(0.05);

g.append("g")
                .attr("class", "axis")
                .call(d3.axisLeft(y).ticks(null, "s"))
                .append("text")
                .attr("x", 2)
                .attr("y", y(y.ticks().pop()) + 0.5)
                .attr("dy", "0.32em")
                .attr("fill", "#000")
                .attr("font-weight", "bold")
                .attr("text-anchor", "start")
                .text("Total Amount");
      
    });
    
    
    
    
    
    //Regression data generator
        function calculateRegression(paramID, data) {
            data.forEach(function (d) {
                d["xNum"] = d3.timeFormat("%m")(new Date(d.key));
                d["value"] = +d.values[0].value;
                d["CHN"] = d.values[0].key;
                d["MTH"] = d.key
            })

//Draw the Regression Line
            //Data Manipulation
            // src : https://bl.ocks.org/ctufts/298bfe4b11989960eeeecc9394e9f118
            // calculate coefficients
            var x_mean = d3.mean(data, function (d) {
                return d["xNum"];
            });
            var y_mean = d3.mean(data, function (d) {
                return d["value"];
            });
            var term1 = 0;
            var term2 = 0;
            var xr = 0;
            var yr = 0;
            for (i = 0; i < data.length; i++) {
                xr = data[i]["xNum"] - x_mean;
                yr = data[i]["value"] - y_mean;
                term1 += xr * yr;
                term2 += xr * xr;
            }

var b1 = term1 / term2;
            var b0 = y_mean - (b1 * x_mean);

// perform regression 
            var yhat = [];
            var temp;
            // fit line using coeffs
            for (i = 0; i < data.length; i++) {
                yhat.push(b0 + (data[i]["xNum"] * b1));
            }
            for (i = 0; i < data.length; i++) {
                temp = {
                    "yhat": yhat[i],
                    "y": data[i]["value"],
                    "x": data[i]["xNum"],
                    "MTH": data[i]["MTH"]
                }
                temp["CHN"] = data[i]["CHN"]
                paramID.push(temp);
            }
        }

</script>
</body>

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