We tend to think of scaling as a unidirectional problem—we can only scale up from where we are currently. Unfortunately, that doesn't quite work. We can only scale in one direction for so long before the foundation crumbles under our feet. The key is in identifying the scaling limitations, and designing around them.

In this chapter, we'll look at the fundamental scaling constraints faced by JavaScript architects in nearly every browser environment. We'll also look at the customer as a scaling influencer, and how new features conflict with existing features. Scaling down from bloated design is an essential activity as well.

The composition of our application as a whole determines how easy or how difficult it'll be to scale down by turning features off. It all has to do with coupling, and if we look closely, we'll often discover that we need to refactor our components so they can be easily removed later on.