[zapzupnz]

This all looks good to me until I'm unwrapping an optional and checking it's length in Swift, which normally looks like:

    guard let array = obj.someArray,
          array.count > 0 else {
        throw SomeError
    }

[saagarjha]

A somewhat stupid way to solve this issue (of what is likely poorly-designed API, given what you're trying to do here; optional Arrays are generally a code smell) is to abuse the nil coalescing operator:

  guard !(obj.someArray?.isEmpty ?? true)

[zapzupnz]

Well sure, except if the array is optional (and I agree it's code smell, but that's what you get when you use other peoples' libraries, I guess) that statement doesn't unwrap the array for me to use; I'll either need to do it manually on a second line (waste of effort) or every time I try accessing that variable. If I access it a lot, this is inefficient duplication.

Plus, I don't like abusing the nil coalescing operator. Once you're abusing anything, you're adding signal to noise and making the intent of a statement less clear than necessarily, I feel.

+1 for isEmpty, though. According to the docs, count iterates over collections that don't conform to RandomAccessCollection, so best to avoid unnecessary overhead by adopting good practice! Thanks for that.

[saagarjha]

In your specific example, it didn't look like you wanted to use that array, so I thought I could save you a variable. If you are planning to use it, then by all means bind it to a variable for reuse.

[zapzupnz]

What other use is there for a conditional let?

[saagarjha]

I thought your only use for the array was to check its count. Now that I think about it, that was probably a stupid assumption.

[deathanatos]

Why can that not be swapped to:

  guard let array = obj.someArray,
        0 < array.count else {
      throw SomeError
  }

?

[zapzupnz]

It could be changed to that, but what am I really asking? "Is zero lower than the length of my array" is a bizarre way to word the question, as opposed to "is the length of my array greater than zero".

I believe in self-documenting and obvious code, and I think if statements should read as much like a human sentence as possible.

[pantalaimon]

`array.count < 1` still sounds reasonable though.

[zapzupnz]

Only if I _want_ the array to be empty, otherwise I have to put an ! in front of the that — which in Swift also needs brackets — which is just adding noise to the signal, really, which really defeats the purpose of avoiding the greater than symbol here.