if an entry isn’t in the base map, it won’t exist in the final one

Yes. Which is why I iterated through

mapOverride

instead. This is a union of both maps with the assumption that they only contain sets/other values and a key always points to values of similar type (or null) in both maps. Entries in

mapOverride

are always preferred except for sets where both will get merged I suppose that is what you’re trying to achieve?

Exactly.

I have one more type to add here:

Map<String, Set<String>>

You mean this as input? The

mergeWith

will handle it as well

Map<String, Map<String, Set<String>>>

Aha. Okay

Any key that exists in override should just reset the set (not add to it...)

This should do that:

fun MutableMap<String, Any>.mergeWith(mapOverride: Map<String, Any>?) {
    mapOverride?.forEach { (k, v) ->
        val baseValue = this[k]
        this[k] = when {
            baseValue is Set<*> && v is Set<*> -> baseValue + v
            baseValue is Map<*, *> && v is Map<*, *> -> baseValue + v
            else -> v
        }
    }
}

Cool! But then, when a key is in override that isn't in base...?

…then it will add it to base

Very nice 😁, thanks alot!

You’re welcome! 🙂