Emily Pillmore

@flip111 that's exactly it. `filterKeys` is something many people do, and so we should optimize for it. The point is convenience. It's very low cost to add it, and i...

Some examples: - [guava](https://guava.dev/releases/19.0/api/docs/com/google/common/collect/Maps.html#filterKeys) - [kotlin](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/filter-keys.html) - [scala](https://www.scala-lang.org/api/2.13.5/scala/collection/MapView$$FilterKeys.html) - alternatively, view the [deprecated version](https://www.scala-lang.org/api/2.13.5/scala/collection/Map.html#filterKeys(p:K=%3EBoolean):scala.collection.MapView[K,V]) which used to act on the map itself. - [purescript](https://github.com/purescript/purescript-ordered-collections/blob/v1.6.1/src/Data/Map/Internal.purs#L675-L675) - [clojure](https://github.com/weavejester/medley/blob/master/src/medley/core.cljc#L149) - they have a...

Looks fine to me, but it's up to @treeowl