MapDelegate from SnakeCase property Name

MapDelegateFromSnakeCase.kt

/**
 * To use delegate property from map, getting value from a snakeCase key
 * 
 * eg.:
 * ```kotlin
 * val myMap = mapOf("hello_world" to "Some Value")
 * val helloWorld: String by myMap.fromSnakeCase()
 * ```
 * 
 * So, the val "helloWorld" will contain "Some Value" 
 */
@Suppress("UNCHECKED_CAST")
fun <T, T1 : T> Map<String, T>.fromSnakeCase() = ReadOnlyProperty<Nothing?, T1> { _, property ->
    this[property.name.fromCamelCaseToSnackCase()] as T1
}

/**
 * Transform a string written as camelCase to snakeCase
 * 
 * eg.:
 * ```kotlin
 * val myValue = "helloWorld".fromCamelCaseToSnackCase()
 * ```
 * 
 * So, the val "myValue" will contain "hello_world
 */
fun String.fromCamelCaseToSnackCase(): String {
    return buildString {
        var prevIsUpperCase = false
        for (char in this@fromCamelCaseToSnackCase) {
            prevIsUpperCase = if (char.isUpperCase()) {
                if (!prevIsUpperCase) {
                    append('_')
                    append(char.lowercase())
                } else {
                    append(char)
                }
                true
            } else {
                append(char)
                false
            }
        }
    }
}