isBlank 
  Since Kotlin
1.0Returns true if this string is empty or consists solely of whitespace characters.
Since Kotlin
1.1Samples
import java.util.Locale
import kotlin.test.*
fun main() { 
   //sampleStart 
   fun validateName(name: String): String {
    if (name.isBlank()) throw IllegalArgumentException("Name cannot be blank")
    return name
}
println(validateName("Adam")) // Adam
// validateName("") // will fail
// validateName("  \t\n") // will fail 
   //sampleEnd
}Returns true if this string is empty or consists solely of whitespace characters.
Since Kotlin
1.0Samples
import java.util.Locale
import kotlin.test.*
fun main() { 
   //sampleStart 
   fun validateName(name: String): String {
    if (name.isBlank()) throw IllegalArgumentException("Name cannot be blank")
    return name
}
println(validateName("Adam")) // Adam
// validateName("") // will fail
// validateName("  \t\n") // will fail 
   //sampleEnd
}Returns true if this string is empty or consists solely of whitespace characters.
Since Kotlin
1.3Samples
import java.util.Locale
import kotlin.test.*
fun main() { 
   //sampleStart 
   fun validateName(name: String): String {
    if (name.isBlank()) throw IllegalArgumentException("Name cannot be blank")
    return name
}
println(validateName("Adam")) // Adam
// validateName("") // will fail
// validateName("  \t\n") // will fail 
   //sampleEnd
}Returns true if this string is empty or consists solely of whitespace characters.
Since Kotlin
1.8Samples
import java.util.Locale
import kotlin.test.*
fun main() { 
   //sampleStart 
   fun validateName(name: String): String {
    if (name.isBlank()) throw IllegalArgumentException("Name cannot be blank")
    return name
}
println(validateName("Adam")) // Adam
// validateName("") // will fail
// validateName("  \t\n") // will fail 
   //sampleEnd
}Returns true if this string is empty or consists solely of whitespace characters.
Since Kotlin
1.8Samples
import java.util.Locale
import kotlin.test.*
fun main() { 
   //sampleStart 
   fun validateName(name: String): String {
    if (name.isBlank()) throw IllegalArgumentException("Name cannot be blank")
    return name
}
println(validateName("Adam")) // Adam
// validateName("") // will fail
// validateName("  \t\n") // will fail 
   //sampleEnd
}