Chapter 4
Pay Off Your Technical Debt

Now that we’ve uncovered hotspots and surprising temporal coupling in our codebase, we need to put that information to use. This is often easier said than done. Even armed with the existing catalogs of refactoring techniques, we need to consider the people side of code, too. Refactoring code that’s under heavy development, perhaps even shared between multiple teams, adds another dimension to the problem.

This chapter introduces refactoring strategies that let you improve code iteratively to limit the disturbance to the rest of the business. The strategies build on the evolutionary analyses you mastered in the earlier chapters, which lets you drive refactoring by using data about how your team works with the code.

This chapter is also the most technical one in the book, so feel free to skip ahead to the next chapter if you’re more interested in the strategic importance of the analysis information. If you’re still here, let’s get ready for proximity—a much underused design principle.