Hi guys, can we improve this code? ```private cons...

# codereview

[KotlinLeaner]

Hi guys, can we improve this code?

private const val BOLD_PATTERN = "<b>(.*?)</b>"
fun main() {
    val message = "Hello, How are you? My Name is <b>Xyz</b>. <b>Abc</b> your next score will be 100 to win the game."
    val itemList = findAndGetBoldList(message)
    val filterMessage = message.replace("<b>", "").replace("</b>", "")
    itemList.forEach { println("Bold part is :- $it") }
    println(filterMessage)
}

fun findAndGetBoldList(message: String): List<String> {
    return BOLD_PATTERN
        .toRegex()
        .findAll(message)
        .map {
            it.value.replace("<b>", "").replace("</b>", "")
        }
        .toList()
}

[Szymon Jeziorski]

Instead of having String pattern as a const val, you can have the regex itself as a top level field - private val BOLD_PATTERN_REGEX = Regex("<b>(.*?)</b>") since it is created the same way each time in findAndGetBoldList.
Also, as you are using a captured group in your regex, you can use it to obtain the string being between <b> opening and closing tags.

BOLD_PATTERN_REGEX
            .findAll(message)
            .map { it.groupValues[1] }
            .toList()

This way is not only cleaner, but also it doesn't duplicate the tag name which is already in the regex. If you would like to change <b> to <strong> for example, above function would still work the same way as you don't have explicit replace duplicating the tag name.

Another note is that within the main function I would rename filterMessage to filteredMessage. filterMessage to me sounds like a message used for filtering, whereas filtered clearly indicates a message that has already been filtered. And again, here you can use Regex API to obtain filtered message instead of using String API for replacement duplicating tag names:
val filterMessage = BOLD_PATTERN_REGEX.replace(message, "$1") - $1 indicates first captured group.
You can also use more verbose API providing replacement programatically:
BOLD_PATTERN_REGEX.replace(message) *{ it*.groupValues[1] *}*