Hello! Is it considered bad practice to define ext...

# announcements

[Gabe Kauffman]

Hello! Is it considered bad practice to define extension functions for native types, such as String ?

Example, putting a function like this globally scoped in like a StringUtils.kt class:

fun String.getLinkIfPresent(): String? {
    val m: Matcher = urlPattern.matcher(this)
    if (m.find()) {
        return m.group().trim()
    }

    return null
}

[Casey Brooks]

Personally, I see no issue with extensions on String. Being one of the most-used and most-flexible classes, it makes sense to wrap common String use-cases into an extension.

Extensions on number or boolean types feels a bit more dirty to me

[Casey Brooks]

I’d probably avoid extensions on numbers or booleans in a library, but they might make more sense in application code, where there might be more of a business-logic reason for it

[Jakub]

Extensions are fine. Depends on a use case. In my opinion in general I would rather avoid extensions that adds logic, it should be more like utilities.
If seems like your extension is using local or global variable urlPattern. This may lead to Singletons which are bad practice.

[Gabe Kauffman]

Got it. Thank you guys