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Intro to Swift and clean coding practices

Intro to Swift and clean coding practices

Mark Wilkinson

February 05, 2020

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  1. All the things properties, optionals classes, structs, enums (super-powerful) blocks

    (with lamba-expression syntax) protocols (interfaces) class and protocol extensions generics
  2. Classes - can inherit from only 1 subclass - can

    implement 1 to many protocols (interfaces)
 - the usual reference type behavior
  3. Structs - cannot inherit from another struct or class -

    can implement 1 to many protocols (interfaces)
 - the usual value type behavior
  4. When to use what - when you need to inherit,

    use a class. - when your type has utility methods, holds properties (like a model object), etc. make it a struct.
 - Immutability should be preferred, thus prefer structs and use a class only when it’s necessary.
  5. The complex programmer • writes cryptic, complex code because they

    can. • never reads programming books or attends meetups, code confs. etc. • no documentation, if you can’t read it, you’re just a bad developer. • basically a ‘lifer’ at the business.
  6. The thoughtful programmer • writes clean, patterned and thoughtful code.

    • always strives for improvement and not for the sake of making more money. • documents code with proper naming, patterns and comments. • uses peer-reviewed pull requests to learn from his mistakes.
  7. clean up optionals with guard • early termination (no need

    to carry on if conditions aren’t met). • cleans by removing if let optional bindings and conditional statements
  8. community agreement on optional unwrapping • prefer to use the

    same name as the optional. • the compiler has no issues, and it will only be local to the method. • The same goes for guard, use the optional’s name for the unwrapped type.
  9. assert yourself • assertionFailures should be used in place of

    many NSLog and print statements. • You the developer need to find crashing conditions early not in QA • Go through every console log (NSLog, print) and replace with error reporting and/or add to them with an assertFailure
  10. • A great place to use them is in fail

    early guard statements. • They are stripped out for a release build (assuming you’re using different builds). • fail early and stop to solve bugs during development and not from a QA bug ticket.
  11. I see dead comments • Comments are part of the

    code, treat them as such • The less noticeable they are, the more likely they’ll go unmaintained • Change their color to stand out more • Pay attention to comments in pull requests.
  12. Take care of warnings • _ = lets you suppress

    the unused result warning, and explicitly tells the reader “I am intentionally ignoring this returned value.” • Follow Xcode’s instructions or fix the code to make the warning go away • Sign of a broken-window-theory project are hundreds of warnings.
  13. Start cleaning • Add a (pragma) mark above every set

    of protocol code (for each) • This gives you a nice visual divider in the code and the quick search drop-down
  14. Extract and extend take the code out of the VC

    and add an extension • naming convention: className+protocol.swift • technically it’s still a part of the class but it reduces the size of the class and organizes the code better.
  15. Lighten the load use the coordinator pattern for viewControllers •

    The heart of the problem is that segues and navigation are usually implemented in the view controllers. • This tightly couples 1 view controller to another. • Remove this responsibility with a Coordinator
  16. Coordinate everything in software should have 1 job. • Every

    view controller gets a coordinator • All vc coordinators are controlled by an AppCoordinator • Makes the ViewControllers do only what they’re supposed to, update the view. • Segues are negated, as the coordinators now control the navigation and app workflow
  17. Prefer protocols • Apple strongly suggests protocol-based development and you

    see it through out CocoaTouch. • Protocols let you swap out dependencies easily at run-time. • Coordinators can hold onto these protocol-based dependencies instead of ViewControllers. • Protocols enforce the you-have-1-job rule better.