Reducing boilerplate with Kotlin - an example

string-contains-any.kt

// how to check if a string contains a number of chars?  

// the java-esque way:

imageNameWithoutExtension.contains('.') || 
    imageNameWithoutExtension.contains('#') || 
    imageNameWithoutExtension.contains('$') ||
    imageNameWithoutExtension.contains('[') || 
    imageNameWithoutExtension.contains(']')

// too much repeated code.

imageNameWithoutExtension.run {
    contains('.') || contains('#') || contains('$') || contains('[') || contains(']')
}

// still too much repeated code. Let's create a .containsAny using Kotlin Extension and functional programming.

fun String.containsAny(vararg chars: Char) = chars.fold(false) { acc, c -> acc || this.contains(c) }

imageNameWithoutExtension.containsAny('.', '#', '$', '[', ']')