Add a filtering function

[neongreen]

Typescript doesn't seem to be smart enough to figure out that filtering with a tag-predicate results in an array of values satisfying the predicate.

Would this be a good addition?

import * as R from 'ramda'

export function filterTag<Tag, T>(xs: T[], p: (x: T) => x is T & Tag): (T & Tag)[] {
  return R.filter(p, xs)
}

[neongreen]

Unfortunately requires a signature at the call site due to microsoft/TypeScript#12798

[neongreen]

Actually nevermind, it doesn't work with my function but does work with xs.filter.