s2.js

const S = {
  
  fromArray: xs => sink => {
    for (let i=0; i<xs.length; ++i)
      if (sink(xs[i]))
        return true
  },

  map: fn => stream => sink => stream(x => sink(fn(x))),

  chain: fn => stream => sink => stream(x => fn(x)(sink)),

  take: n => stream => sink => {
    let i = 0
    return stream(x => {
      if (i === n || (++i, sink(x)) || i === n)
        return true
    })
  },

  toArray: stream => {
    const xs = []
    stream(x => { xs.push(x) })
    return xs
  }
};

const suits = ['♠', '♥', '♦', '♣']
const ranks = ['1', '2', '3', '4', '5', '6', '7', '8', '9', 'J', 'Q', 'K', 'A']


S.toArray(
  S.take(2)(
    S.chain(suit => S.map(rank => suit+rank)(S.fromArray(ranks)))
           (S.fromArray(suits))))

stream-again.js

// credit to Vesa Karvonen (@polytypic) for this implementation
//
const suits = ['♠', '♥', '♦', '♣']
const ranks = ['1', '2', '3', '4', '5', '6', '7', '8', '9', 'J', 'Q', 'K', 'A']

// Processes one item at a time.  Does not fuse in V8,
// which requires you to use methods to achieve fusion.

const S_fromArray = xs => sink => {
  for (let i=0; i<xs.length; ++i)
    if (sink(xs[i]))
      return true
}

const S_map = fn => stream => sink => stream(x => sink(fn(x)))

const S_chain = fn => stream => sink => stream(x => fn(x)(sink))

const S_take = n => stream => sink => {
  let i = 0
  return stream(x => {
    if (i === n || (++i, sink(x)) || i === n)
      return true
  })
}

const S_toArray = stream => {
  const xs = []
  stream(x => { xs.push(x) })
  return xs
}

S_toArray(
  S_take(2)(
    S_chain(suit => S_map(rank => suit+rank)(S_fromArray(ranks)))
           (S_fromArray(suits))))