Pipe Classes

In the last section, we created a new class, UserIsActiveAdmin, and ended up with this:

const activeAdminCanEdit: boolean = new UserIsActiveAdmin(user).invoke() 
    && user.canEdit();
if(activeAdminCanEdit) {
    // Do stuff.
}

Building these kinds of classes that deal with a single test or condition helps us to build lots of smaller pieces that we can later combine together for more complex scenarios.

This refactoring is useful, but I want to show you an even more flexible way to build these classes.

Your Classes Might Be Doing Too Much...

Looking at the code sample at the beginning of the chapter, what if we wanted to further combine all the logic into a single class?

We might call it UserIsActiveAdminAndCanEdit. Okay.

And that might be fine. But what if we have, let's say, eight different conditionals we need to check here?

Our class might have this name:

CheckOneCheckTwoCheckThreeCheckFourCheckFiveCheckSixCheckSevenCheckEight...