We live in a world of scarcity. Resources are finite. In order to write the best possible code, we need to take this scarcity into account. So, when designing and implementing our ideas, we should be doing so with an eye toward efficiency.

In this section, we'll explore the different facets of efficiency and tie them into the world of JavaScript through examples. Hopefully, you will come away with an appreciation for how efficiency is not only about going fast but that it encompasses many indirect effects, spanning the gamut from economy to ecology.