fun CharSequence?.isNullOrBlank(): Boolean
Returns true
if this nullable char sequence is either null
or empty or consists solely of whitespace characters.
import kotlin.test.*
fun main(args: Array<String>) {
//sampleStart
fun validateName(name: String?): String {
if (name.isNullOrBlank()) throw IllegalArgumentException("Name cannot be blank")
// name is not nullable here anymore due to a smart cast after calling isNullOrBlank
return name
}
println(validateName("Adam")) // Adam
// validateName(null) // will fail
// validateName("") // will fail
// validateName(" \t\n") // will fail
//sampleEnd
}
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https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.text/is-null-or-blank.html