kotlin.text.substringBefore

substringBefore

fun String.substringBefore(
    delimiter: Char, 
    missingDelimiterValue: String = this
): String

fun String.substringBefore(
    delimiter: String, 
    missingDelimiterValue: String = this
): String

Returns a substring before the first occurrence of delimiter. If the string does not contain the delimiter, returns missingDelimiterValue which defaults to the original string.