SLAP

SRP and SLAP: Keys to maintainable and readable code

In this post, we’ll take a look at two principles to apply to your code to make sure it’s as clear, readable, and maintainable as possible: SRP and SLAP.

Single responsibility principle (SRP)

The idea behind the single responsibility principle (SRP) is that every class, module, or function in a program should have one responsibility/purpose.

In other words, every class should have only one reason to change.

It is restating the importance of cohesion in code.

What violates SRP?

Let’s say a developer sees something like this in a user class:

changeAddress() 
login() 
logout()

Those three steps violate SRP. The functions should be separated.

You probably agree that long functions aren’t a good idea, but you’ve probably also seen them at work recently. So, how long is long? A thousand lines is definitely long, but 100? 25?

How long should be functions?

The answer is that there is no standard.However, if someone says that a function isn’t long if they can see the entire thing in one window, my question would be, What is your font size? :D

A way to rethink long functions

To demonstrate the single responsibility principle, let’s imagine two versions of a conversation with a colleague of yours — the one who writes long functions. The first version represents the SRP.

Conversation 1

Them: How was your weekend?

You: It was great, I went to the park on Saturday, and a movie on Sunday.

Them: Really? Which park?
You: The one by the main street.
Them: Is that family-friendly?

Conversation 2

Them: How was your weekend?

You: Oh, my weekend?! At 7 a.m. I took the car out of the garage, drove for 3 kilometers, turned right, went 4 more kilometers, and they had a detour. Can you imagine the mess they have on the roads? I turned around, then it started raining. There…