Modular programming

My notes on modular programming

“And you can easily swap blocks. Want a new camera in the app? Change the camera framework, API remains more or less the same”


  • Modular: single ‘responsibility’
  • monolith: tightly coupled
  • abstract systems into manageable layers

Benefits of modular programming:

  • Speed of implementing new stuff,
  • Modularity and easily change components of the app,
  • Scalability of the team, easier to find it’s way around, make programmers happy
  • Modules are reusable across projects
  • Each one have a independent test app, tests (and repo of course)
  • Carthage, new functionality goes into a framework. For instance if you make a new password strength checker -> own framework
  • Keeping time-saving-extensions in classes makes them prone to becoming out of sync with other parts of the code
  • Many modern apps often have 20-40 internal .framework dependencies
  • Divided project into logical parts that are living their life.
  • Developers can run and develop only specific parts of the app (specific framework) without compiling everything.
  • More flexibility on the project. A framework can be quite easily taken out or linked back into the project.
  • Develop more efficiently using XCPlaygrounds as a project cannot be imported to the XCPlaygrounds but a framework can. A perfect use case is for developing UIComponents. With Playgrounds there is almost an instant build of the view.
  • Every framework contains its unit tests so it can be run in isolation from the rest of the app.
  • Developers can work more async, isolated on their own tasks without disturbing progress of the main project
  • Modules can live isolated while other modules move on by using legacy versions of dependencies
  • Access control (limit with the internal accessor, only make public methods that can be accessed from outside)
  • Shorter more explicit naming of classes: Not RemoteImageAccessManipulator but rather just internal AccessManipulator in a RemoteImage module

Nails monolith vs modular:

Additional reading: