How can I write this code without repeating `chang...

# getting-started

[Daniele B]

How can I write this code without repeating changed twice ?

val changed = changeSelectedCounty()
if (changed) {
    showDetail()
}

I am looking for something like this, but it’s not accepted:

if (val changed = changeSelectedCounty()) {
    showDetail()
}

I would to assign the result to the changed variable, as it gives more clarity

[nanodeath]

I can think of a goofy way...

changeSelectedCounty().takeIf { changed -> changed }?.let { showDetail() }

but that's almost certainly confusing

[nanodeath]

oh, if you want to be really explicit you can return an enum

if (changeSelectedCounty() == CHANGE_OCCURRED) { showDetail() }

but...might be overkill

[nanodeath]

tbh I think just using a named variable is fine. "Clean Code" recommends creating more variables than you strictly need to for documentation purposes.

[Daniele B]

thanks! yes, I think I will keep the named variable

[Cedrick Cooke]

Another alternative, something like this should work

when (val changed = changeSelectedCounty()) {
    true -> showDetail()
}

[Brian Dilley]

changeSelectedCounty() ?: showDetail()

[Brian Dilley]

not sure if that would work actually

[nanodeath]

that'll only execute showDetail if changed is null

[itbhp]

Add a query method countyChanged that calls the command method 'changeSelectedCountry' and return the outcome, then use it instead of a local variable

[Akindele Beulah]

@Brian Dilley Kotlin has tenary?

[itbhp]

Brian's code is not an example of a ternary operator: the ?: I think it is called Elvis operator. It is used to do something when the left part is null.

[itbhp]

And no Kotlin doesn't have ternary operator

[Brian Dilley]

right, no ternary and it’s a null thing

[Brian Dilley]

btw:

val changed = if (changeSelectedCountry()) { true } else { false }

[nanodeath]

I mean, you can, but why