Using a closure ``` fun lt T gt LiveData lt T gt distinct LiveData lt T gt var lastValue Any = Any return MediatorLiveData lt T gt apply addSource this distinct if it = lastValue lastValue = it postValue it ``` Or using a property of the object ``` fun lt T gt LiveData lt T gt distinct LiveData lt T gt return MediatorLiveData lt T gt apply addSource this distinct object Observer lt T gt private var lastValue Any = Any override fun onChanged value T if value = lastValue lastValue = value postValue value ``` Any arguments to prefer one over the other

Using a closure ``` fun lt T gt LiveData lt T gt distinct Li kotlinlang #announcements

01/14/2018, 12:07 PM

Using a closure:

fun <T> LiveData<T>.distinct(): LiveData<T> {
    var lastValue: Any? = Any()

    return MediatorLiveData<T>().apply {
        addSource(this@distinct) {
            if (it != lastValue) {
                lastValue = it
                postValue(it)
            }
        }
    }
}

Or using a property of the object:

fun <T> LiveData<T>.distinct(): LiveData<T> {
    return MediatorLiveData<T>().apply {
        addSource(this@distinct, object : Observer<T> {

            private var lastValue: Any? = Any()

            override fun onChanged(value: T?) {
                if (value != lastValue) {
                    lastValue = value
                    postValue(value)
                }
            }

        })
    }
}

Any arguments to prefer one over the other?

01/14/2018, 1:20 PM

second is less readable

01/14/2018, 4:33 PM

the closure is definitely more readable