Extracting Conditional Logic to Explicit Classes

In the previous section, we looked at extracting conditional logic as new methods on a user object.

Sometimes, though, we end up doing this refactoring over and over.

What we are left with is a User class that is filled with tons of these kinds of methods.

Note

This can be an issue that is best solved by actually modeling your classes using a domain-driven design approach.

While being beyond what this book covers, you might be interested in looking into the concept of bounded contexts (https://www.martinfowler.com/bliki/BoundedContext.html).

Let's Get Classy

Imagine that our User class looked something like this now:

class User {
    isAdmin(): boolean { /* Code */ }
    isActive(): boolean { /* Code */ }
    canEdit(): boolean { /* Code */ }
    isActiveAdmin(): boolean { /* Code */ }
    isActiveAdminThatCanEdit(): boolean { /* Code */ }
    // And dozens of more methods...
}

You can tell that this...