```// `cache` is an interface that has method `new...

# codingconventions

[miqbaldc]

// `cache` is an interface that has method `newToken()` & `unrecoverableSession()`

Which one do you guys prefer, on the following snippet code?

1️⃣

if (retryCount > RETRY_LIMIT) {
             cache.unrecoverableSession()
             return null
        }

        cache.newToken()?.let { newToken ->
             return rewriteRequest(newToken)
        }

        return null

or

2️⃣

if (retryCount > RETRY_LIMIT) {
            cache.unrecoverableSession()
            return null
        }

        val newToken = cache.newToken()

        return if (newToken != null) {
            rewriteRequest(newToken)
        } else {
            cache.unrecoverableSession()
            null
        }

or

3️⃣

val newToken = cache.newToken()

        return when {
            retryCount > RETRY_LIMIT -> {
               cache.unrecoverableSession()
               null
            }
            newToken != null -> rewriteRequest(newToken)
            else -> {
               cache.unrecoverableSession()
               null
            }            
        }

[Luke]

Here is a more functional style which does the same if I'm not mistaken. One upside here is that whenever you are to return null, cache.unrecoverableSession() is run, unlike 1️⃣ in which you forgot one call

return cache
    .takeUnless { retryCount > RETRY_LIMIT }
    ?.newToken()
    ?.let(::rewriteRequest)
    .also { if (it == null) cache.unrecoverableSession() }

[Tobias Berger]

@Luke definitely possible, but somehow I don't like using takeIf/Unless when I'm not checking anything o the receiver. For me that's more of a validation/filter function than something for controlling code flow. A simple it-condition is much easier to read and understand than this chain.

[Tobias Berger]

@miqbaldc I suggest flipping the first if-clause and doing something like this:

if (retryCount <= RETRY_LIMIT) {
    cache.newToken()?.let {
        return rewriteRequest(it)
    }
}

cache.unrecoverableSession()
return null