Hanoi Tower recursive to iterative

hanoi.js

// recursive 
const hanoi0 = (n, a, b, c) => {
  if (n > 0) {
    hanoi0(n - 1, a, c, b);
    console.log(`${a} ==> ${c}`);
    hanoi0(n - 1, b, a, c);
  }
}
hanoi0(3, "a", "b", "c");

console.log("--------------------");

// CPS style
const hanoi1 = (n, a, b, c, k) => {
  if (n > 0) {
    hanoi1(n - 1, a, c, b,
      () => {
        console.log(`${a} ==> ${c}`);
        hanoi1(n - 1, b, a, c, k);
      });
  }
  else {
    k();
  }
}
hanoi1(3, "a", "b", "c", () => { });

console.log("--------------------");

// CPS style
const hanoi2 = (n, a, b, c, k) => {
  if (n > 0) {
    hanoi2(n - 1, a, c, b,
      () => {
        console.log(`${a} ==> ${c}`);
        hanoi2(n - 1, b, a, c, k);
      });
  }
  else {
    k();
  }
}
hanoi2(3, "a", "b", "c", () => { });

console.log("--------------------");

// Defunctionalising the continuation
// type cont = {n:int , a:string, b:string, c:string, next:cont} | null

const hanoi3 = (n, a, b, c, k) => {
  while (true) {
    if (n > 0) {
      k = { n: n, a: a, b: b, c: c, next: k }; // new cont (stack push)
      [a, b, c] = [a, c, b];
      n = n - 1;
    } else {
      if (k != null) {
        console.log(`${k.a} ==> ${k.c}`);
        [a, b, c] = [k.b, k.a, k.c];
        n = k.n - 1;
        k = k.next; // (stack pop) 
      }
      else {
        return;
      }
    }
  }
}
hanoi3(3, "a", "b", "c", null);