Code from the fantas-eel post on ChainRec.

chainRec.js

const daggy = require("daggy");

const { Loop, Done } = daggy.taggedSum("Loop", {
  Loop: ["b"],
  Done: ["a"]
});

Array.empty = () => [];

const Pair = T => {
  const Pair_ = daggy.tagged("Pair", ["_1", "_2"]);

  Pair_.prototype.map = function(f) {
    return Pair_(this._1, f(this._2));
  };

  Pair_.prototype.ap = function(fs) {
    return Pair_(fs._1.concat(this._1), fs._2(this._2));
  };

  Pair_.of = x => Pair_(T.empty(), x);

  Pair_.prototype.chain = function(f) {
    const that = f(this._2);

    return Pair_(this._1.concat(that._1), that._2);
  };

  Pair_.chainRec = function(f, init) {
    let acc = T.empty(),
      step = Loop(init);

    do {
      const result = f(step.b);

      acc = acc.concat(result._1);
      step = result._2;
    } while (step instanceof Loop);

    return Pair_(acc, step);
  };

  return Pair_;
};

const Writer = Pair(Array);

const seqRec = upper =>
  Writer.chainRec(
    init => Writer([init], init >= upper ? Done(null) : Loop(init + 1)),
    0
  );

const seq = upper => {
  const seq_ = init =>
    init >= upper ? Writer([init], null) : Writer([init], init + 1).chain(seq_);

  return seq_(0);
};

// console.log(seq(10000)._1) // Will fail
console.log(seqRec(10000)._1);