import kotlin.io.encoding.Base64
import kotlin.io.encoding.ExperimentalEncodingApi

// *** before: ***
// java.util.Base64.getEncoder().encodeToString(bytes)   // the JVM only

// *** in version 1.8: ***  (1.8.20, experimental)
@OptIn(ExperimentalEncodingApi::class)
fun main() {
    val encoded = Base64.Default.encode("Kotlin".encodeToByteArray())
    println(encoded)                          // S290bGlu

    val decoded = Base64.Default.decode(encoded)
    println(decoded.decodeToString())         // Kotlin

    // a variant safe for URLs and file names
    println(Base64.UrlSafe.encode(byteArrayOf(-5, -1, 0)))
}