How do you find the minimum, maximum, and average of values of a set of samples over time? What if some of your data sources are unreliable and prone to drop in and out? Should you group them into regular buckets, even if that may mean multiple samples from source A and none from source B? Or should you calculate instantaneous aggregate numbers whenever a new sample comes in at the expense of having as many aggregate points as samples and potentially unevenly distributed across time? Are there better ways?
In the end I hacked up a simple library, aggregate.js, to test various strategies using Node. Right now I just have the two basic windowing and instantaneous strategies implemented, but I plan on adding more as needed.