InsertSectionHeader Paging 3

insertSecionHeader.kt

public inline fun <reified T : R, R : Any, C : Any> PagingData<T>.insertSectionHeader(
    crossinline sectionBy: suspend (T) -> C,
    crossinline insert: suspend (T) -> R,
): PagingData<R> {
    return insertSeparators { first: T?, second: T? ->
        if(first == null && second != null)
            return@insertSeparators insert(second)

        if(second == null) return@insertSeparators null

        if(first !is T) return@insertSeparators null

        val firstSectionByValue = sectionBy(first)
        val secondSectionByValue = sectionBy(second)

        if(firstSectionByValue != secondSectionByValue) {
            insert(first)
        } else {
            null
        }
    }
}