CrossEye

const Loop = (fn, ... init) => { 
  let r = fn (... init)
  while (r instanceof Recur) r = fn (... r)
  return r
}

// Fixed based on a SO discussion: https://stackoverflow.com/a/78940799
const Recur = function ( ...v) {
  return  Object .create (
    Recur .prototype, 

CrossEye

// https://stackoverflow.com/a/75251817

// crawl :: ((a -> Promise b), (b -> [a]), (b -> c), ((Map a c) -> d), Int?) -> [a] -> Promise d
const crawl = (search, extract, convert, collect, simul = 1) => async (inits) => {
  const toCheck = new Set (inits)
  const found = new Map ()
  while (toCheck .size !== 0) {
    const nextBlock = [...toCheck .values ()] .slice (0, simul)
    const results = await Promise .all (nextBlock .map ((x) => search (x)))
    results .forEach ((res, i) => {