Many years ago, I took part in the development of a taxi-hailing mobile app that is still widely used today. I don’t know what kind of code they’re running now, but in those early days, the driver assignment code –if I remember it correctly– was similar in spirit to the grossly simplified example that follows. There are five levels of nested if statements in less than 30 lines of code. It doesn’t look so bad, some might say, but it’s not difficult to imagine how complicated this code can become with just a few more checks…
In case you’re wondering about the down votes, many don’t think Clean Code is not a good book. It got a few good advice, but it also got bad advice disguised as good advice.
I don’t think switch statements should always be avoided. There are cases where polymorphism makes things more difficult to maintain. Saying polymorphism should be used over switch statements is not a good advice.
Here’s an article going into more detail why we should stop recommending Clean Code: https://qntm.org/clean