isNullOrBlank

inline fun CharSequence?.isNullOrBlank(): Boolean(source)

Returns true if this nullable char sequence is either null or empty or consists solely of whitespace characters.

Since Kotlin

1.0

Samples

import java.util.Locale
import kotlin.test.*

fun main() { 
   //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
}
xxxxxxxxxx
 
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 
Open in Playground →
Target: JVMRunning on v.2.1.20

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