Trouble using DC.js (crossfilter and d3 convenience library) - bar chart not showing values

crossfilter, d3.js, dc.js, javascript

Solution

Maybe the `data.report` array is not sorted by timestamp (the sample provided is unsorted). In your code, you assume that those values are sorted. You can try using

// Compute the timestamp extent
var timeExtent = d3.extent(data.report, function(d) { return d.timestamp; });

dc.barChart("#graphTimeOverview")
    // more settings here
    .x(d3.time.scale().domain(timeExtent.map(function(d) { return new Date(d); })))
    .round(d3.time.hour.round)
    .xUnits(d3.time.hours)
    .renderHorizontalGridLines(true);

It would be easier to tell what is the problem if you provide a jsFiddle.

Problem

I am using this library: Dimensional Charting to build some relatively standard charts that need CrossFilter functionality. I have been following the examples but they aren't working for me. Here is my code: ``` var dashData = crossfilter(data.report), dataByHour = dashData.dimension(function(d){ return d3.time.hour(new Date(d.timestamp))}), totalByHour = dataByHour.group().reduceSum(function(d) { return d.amount }), dc.barChart("#graphTimeOverview") .width(990) // (optional) define chart width, :default = 200 .height(250) // (optional) define chart height, :default = 200 .transitionDuration(500) // (optional) define chart transition duration, :default = 500 .margins({top: 10, right: 50, bottom: 30, left: 40}) .dimension(dataByHour) // set dimension .group(totalByHour) // set group .elasticY(true) .centerBar(true) .gap(1) .x(d3.time.scale().domain([new Date(data.report[0].timestamp), new Date(data.report[(data.report.length - 1)].timestamp)])) .round(d3.time.hour.round) .xUnits(d3.time.hours) .renderHorizontalGridLines(true); dc.renderAll(); ``` I know the crossfilter data is working correctly, here is a sample of the group: ``` totalByHour: [ {key:(new Date(1361746800000)), value:6170.17}, {key:(new Date(1361678400000)), value:3003}, {key:(new Date(1361581200000)), value:2350.42}, {key:(new Date(1361667600000)), value:1636.19}, etc... ] ``` Unfortunately all this gets me is an empty graph, it seems to compute the y-axis correctly, so it would seem to me that it can read the data, however I never see any bar values:

Original source