I encountered some issues while working with a Histogram chart using d3, as demonstrated in this example. After plugging in my data, I noticed strange side effects such as retained information from previous datasets on the x-axis scale even after refreshing to a new dataset. I attempted different solutions like deleting and appending a new x-axis, but nothing seemed to work.

The root cause of this problem was that my datasets had varying x-axis ranges and scales. The only effective solution I found was to remove the entire svg element and then re-append everything afresh. However, this abrupt transition was not user-friendly. Hence, I wanted to explore better ways to handle dataset refreshes with smooth transitions, similar to the original example, even when dealing with datasets with different x-scales and ranges.

The approach I last tried felt jarring:

// delete old
d3.select("#" + divId).select("svg").remove();

// then recreate all new

In an attempt to improve this process of refreshing the dataset (integrated with AngularJS), I followed a step-by-step method. I initialized common parameters first and then checked if the SVG element existed. If it did not exist, I added everything new; otherwise, I tried to update it. Despite going through the code bit by bit, I couldn't figure out why the refresh function failed to eliminate all previous dataset information related to the x-axis scale.

var divId = $scope.histogramData.divId;
var color = $scope.histogramData.color;
var values = $scope.histogramData.data[$scope.histogramData.selected];
var svg = $scope.histogramData.svg;

// Common plot initialization
var margin = {top: 40, right: 20, bottom: 20, left: 20},
    width = 450 - margin.left - margin.right,
    height = 370 - margin.top - margin.bottom;

var max = d3.max(values);
var min = d3.min(values);
var x = d3.scale.linear()
    .domain([min, max])
    .range([0, width]);

// Generate a histogram with twenty uniformly-spaced bins.
var data = d3.layout.histogram()
    .bins(x.ticks(10))
    (values);

var yMax = d3.max(data, function(d){ return d.length });
var yMin = d3.min(data, function(d){ return d.length });
var colorScale = d3.scale.linear()
    .domain([yMin, yMax])
    .range([d3.rgb(color).brighter(), d3.rgb(color).darker()]);

var y = d3.scale.linear()
    .domain([0, yMax])
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

// ===================================================================
// Adding everything anew if SVG doesn't exist
// ===================================================================
if (svg === undefined) {
    var svg = d3.select("#" + divId)
        .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 + ")");
    $scope.histogramData.svg = svg;

    var bar = svg.selectAll(".bar")
        .data(data)
        .enter()
        .append("g")
        .attr("class", "bar")
        .attr("transform", function(d) { return "translate(" + x(d.x) + "," + y(d.y) + ")"; });

    bar.append("rect")
        .attr("x", 1)
        .attr("width", (x(data[0].dx) - x(0)) - 1)
        .attr("height", function(d) { return height - y(d.y); })
        .attr("fill", function(d) { return colorScale(d.y) });

    bar.append("text")
        .attr("dy", ".75em")
        .attr("y", -12)
        .attr("x", (x(data[0].dx) - x(0)) / 2)
        .attr("text-anchor", "middle")
        .text(function(d) { return formatCount(d.y); });

    var gTitle = svg.append("text")
        .attr("x", 0)
        .attr("y", 0 - (margin.top / 2))
        .attr("text-anchor", "left")
        .classed("label", true)
        .text($scope.histogramData.spec[selected]);
    $scope.histogramData.gTitle = gTitle;

    var gAxis = svg.append("g")
     .attr("class", "x axis")
     .attr("transform", "translate(0," + height + ")")
     .call(xAxis);
     $scope.histogramData.gAxis = gAxis;

} else {
    // ===================================================================
    // Attempting to refresh if the SVG exists
    // ===================================================================
    var bar = svg.selectAll(".bar").data(data);

    

    bar.exit().remove();
    
    bar.transition()
        .duration(1000)
        .attr("transform", function(d) { return "translate(" + x(d.x) + "," + y(d.y) + ")"; });

    bar.select("rect")
        .transition()
        .duration(1000)
        .attr("height", function(d) { return height - y(d.y); })
        .attr("fill", function(d) { return colorScale(d.y) });

    bar.select("text")
        .transition()
        .duration(1000)
        .text(function(d) { return formatCount(d.y); });

    var gTitle = $scope.histogramData.gTitle;
    gTitle.transition()
          .duration(1000)
          .text($scope.histogramData.spec[selected]);

    var gAxis = $scope.histogramData.gAxis;
    gAxis.transition()
         .duration(1000)
         .call(xAxis);
}