How to flatten an array of options? about fp-ts HOT 6 CLOSED

import { compact } from 'fp-ts/lib/Array';
declare const as: Array<Option<number>>
const bs: Array<number> = compact(as)

import { Option, some, none } from 'fp-ts/lib/Option'
import * as array from 'fp-ts/lib/Array'
import { identity } from 'fp-ts/lib/unction'

export function mapOption<A, B>(f: (a: A) => Option<B>, as: Array<A>): Array<B> {
  return array.chain(a => f(a).fold(() => array.empty(), array.of), as)
}

export function catOptions<A>(as: Array<Option<A>>): Array<A> {
  return mapOption<Option<A>, A>(identity, as)
}

const as = [none, some(1), none, some(2)]
console.log(catOptions(as)) // => [1, 2]