Question: I want to add two classes to a div, the first class should always apply but the second class only applies when the condition is true else it is not applied. I tried the piece of code below but I don't seem to get the desired result. something could be wrong with my approach.

`<div className={[style.carousalItem, pics.indexOf(item) === this.state.current ? style.currentItem : ''].join(" ")}>`

Answer: 
We were not able to reproduce in another application from scratch.
Therefore we add to proceed the other way around: strip our current application until the problem wasn't here anymore.
First step was to tear down to only an AppDelegate and a simple piece of code but the problem was still here.
We removed all the dependencies from cocoapods but the problem was still here.
We eventually removed a framework that we added directly into the project and it was the culprit!

The said framework is `BiometricSDK` (from IDEMIA). We will send them a mail to know if they are aware of this issue and if they have fixed / will fix it in a newer release. It isn't open-source so I don't know what the specific issue was, my only guess it's that they somehow changed appearance of UIBarButtonItems (yet I'm not sure how their code invoked since we had removed any reference to it while stripping down the application).
This issue might occur when you set title text attribute `foregroundColor` of the `UIBarButtonItem` to `UIColor.clear`.

You could do this directly, eg.:

```swift
navigationItem.rightBarButtonItem?.setTitleTextAttributes([.foregroundColor: UIColor.clear], for: .normal)

```

or by modifying the appearance of the `UIBarButtonItem`, eg:

```swift
UIBarButtonItem.appearance().setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.clear], for: .normal)

```

Check your code, maybe you have such setting somewhere.