Pseudocode for making a cumulative line chart with Keen IO series data. Use this to make a running total of users, for example. The gist assumes that the timeframe being queried includes all of the data.

gistfile1.js

Keen.onChartsReady(function() {
 
  var series = new Keen.Series("registrations", {
    analysisType: "count",
    timeframe: "last_30_weeks",
    interval: "weekly"
  });
  
    series.getResponse(function(response){
        keenData = response.result;
        
        cumulativeData = []  // create a new object to store the cumulative data results
        
        runningTotal = 0 
 
        for each result in keenData {
            registrations = keenData["result"]
            runningTotal = runningTotal + registrations
            newDataPoint =  {
               "value": runningTotal,
               "timeframe": keenData["timeframe"]
             }
            cumulativeData << newDataPoint
            i++
        }
 
         //Create a LineChart visualization 
        var myLineChart = new Keen.LineChart("placeholder", {
            height: "300",
            width: "600",
            title: "cumulative registrations"
        });
        //Draw the visualization into a div
        myLineChart.draw(document.getElementById("myDiv"), cumulativeData);
        })
    })
});