data visualization to the end user developed crossfilter to allow their customers extremely speedy slice and dice on their payment history crossfilter is not the only javascript library capable of mapreduce processingbut it most certainly does the jobis open sourceis free to useand is maintained by an established company (squareexample alternatives to crossfilter are map jsmeguroand underscore js javascript might not be known as data crunching languagebut these libraries do give web browsers that extra bit of punch in case data does need to be handled in the browser we won' go into how javascript can be used for massive calculations within collaborative distributed frameworksbut an army of dwarfs can topple giant if this topic interests youyou can read more about it at js can safely be called the most versatile javascript data visualization library available at the time of writingit was developed by mike bostock as successor to his protovis library many javascript libraries are built on top of js nvd jsxchartsand dimple offer roughly the same thingan abstraction layer on top of jswhich makes it easier to draw simple graphs they mainly differ in the type of graphs they support and their default design feel free to visit their websites and find out for yourselfnvd -- js--xcharts--dimple--many options exist so why dc jsthe main reasoncompared to what it deliversan interactive dashboard where clicking one graph will create filtered views on related graphsdc js is surprisingly easy to set up it' so easy that you'll have working example by the end of this as data scientistyou already put in enough time on your actual analysiseasy-to-implement dashboards are welcome gift to get an idea of what you're about to createyou can go to the following websiteclick around the dashboard and see the graphs react and interact when you select and deselect data points don' spend too long thoughit' time to create this yourself as stated beforedc js has two big prerequisitesd js and crossfilter js js has steep learning curve and there are several books on the topic worth reading if you're interested in full customization of your visualizations but to work with dc jsno knowledge of it is requiredso we won' go into it in this book crossfilter js is another matteryou'll need to have little grasp of this mapreduce library to get dc js up and running on your data but because the concept of mapreduce itself isn' newthis will go smoothly