Javascript Array De-duplication (make items unique)

arrayDedupe.js

// There are a lot of ways to handle this need. This one is great for performance in all envs.
const removeDups = xs => {
  const collect = (r, x) => {
    if (!r.seen[x]) {
      r.result.push(x);
      r.seen[x] = true;
    }
    return r;
  };
  return xs.reduce(collect, { seen: {}, result: [] }).result;
};

const xs = [10, 23, 23, 22, 10, 3, 3, 4, 5];

console.log(removeDups(xs));