Does Crossfilter require a flat data structure?

Question

All the examples of Crossfilter I\'ve found use a flat structure like this:

[
  { name: “Rusty”,  type: “human”, legs: 2 },
  { name: “Alex”,   type: “human”, le         


        

Answer 1

Crossfilter works on an array of records, with each element of the array being mapped to one or more values via dimensions (which are defined using accessor functions).

Even if your data contains aggregate results, you can use this with Crossfilter, but note that it's technically impossible to combine data that has been aggregated across different dimensions, such as combining the "by day" and "by source" data in your example above. You could create a Crossfilter for each aggregated dimension, e.g. one for "by day", and run queries and groups on this, but I'm not sure how useful that would be compared with what you already have.

As for memory usage, are you sure flattening your flattened structure would really be that problematic? Bear in mind that each record (element of the flattened array) can contain references to strings and other objects in your nested structure, so you wouldn't necessarily use up all that much memory.