Practice for returning a value or equivalent variable?

Question

I think it would be easiest to explain what I'm asking with an example.

function getLastNode() {

    let current = this.head;

    if (current == null) {
        // Here, we could either return current, or return null
    }

    while (current.getNext() != null) {
        current = current.getNext();
    }

    return current;
}

---

In the beginning of the function, in the if statement, we have a choice to either write the return statement as return current or return null. In situations like this you could choose either option since they are equivalent.

To avoid this question being considered primarily opinion-based, I want to know if there is any type of convention for this. Is there a standard, convention, or style guide that specifies a standard practice?

Thanks!

Answer 1

Two things to always consider:

1. Consider which leaves your code most responsive to change

2. Consider which is easier to read

1 might argue for current if the flag value might ever be something other than null, I don't see that happening myself.

2 argues for null because it says flat out: if you're here, you're returning null. Even makes life in the debugger easier.

On balance, I'll take return null here.

_{The views presented here should in no way be construed as an endorsement of null.}

Answer 2

Instead of having a separate return for the empty list, I'd just put the while loop into an if(current != null) { block and then return current unconditionally.

It's not always necessary to avoid multiple returns in a method, but if it's possible and even makes the code more succinct, you should do it.