[kotlin] camelToSnake

fun camelToSnake(camel: String): String {
    if (StringUtils.isEmpty(camel)) {
        return ""
    }

    var result = camel[0].lowercase()
    for (i in 1 until camel.length) {
        val t = camel[i]

        if (t.isUpperCase()) {
            result += "_"
        }

        result += t.lowercase()
    }

    return result
}

https://www.geeksforgeeks.org/convert-camel-case-string-to-snake-case-in-java/

Convert camel case string to snake case in Java - GeeksforGeeks