Simple implementation of last step of the random condorcet toss

rank.js

const echo = m => console.log(m);
const rand = (max, min = 0) => Math.ceil(Math.random() * (max - min) + min);
const even = x => x % 2 == 0;
const rank = (stack) => {
  const f = (b) => {
    if(b.length == 0) return; // shouldn't happens
    if(b.length == 1) {
      echo(b[0]);
      return;
    }
    const x = rand(b.length - 1);
    const p = b[x];
    echo(p);
    f(b.filter((v, i) => i !== x));
  };
  stack.forEach(e => f(e));
};

// example
rank([[1], [2, 3, 4], [5, 6, 8]]);