"apiBaseUrl"  -> "api_base_url"

str.split("(?=[A-Z])".toRegex()).joinToString("_") { it.toLowerCase() }

fun String.pascalToSnakeCase() = map { char ->
        if (char.isUpperCase()) "_${char.toLowerCase()}" else char
    }.joinToString("")

"camelCase".split(Regex("(?=[A-Z])")).joinToString(separator = "_", transform = String::toLowerCase)

val capitalRegex = "([A-Z])".toRegex()

    fun String.snakify() = this.replace(capitalRegex) {
        '_' + it.value.toLowerCase()
    }.trim('_')

    @Test
    fun `test pascalToSnake`() {
        "".snakify() shouldBe ""
        "abc".snakify() shouldBe "abc"
        "aBc".snakify() shouldBe "a_bc"
        "someThingElse".snakify() shouldBe "some_thing_else"
    }

str.split(Regex("(?=[A-Z])")).joinToString("_", String::toLowerCase)

str.split(Regex("(?=[A-Z])")).joinToString("_") { it.toLowerCase() }