The Sindresorhus Approach for finding unique random elements from an Array

script.js

var input = [11, 12, 13, 55, 34, 66, 88, 12, 98, 67, 12, 66, 53, 23];
console.log(`input size is ${input.length}`);


(function theSindresorhusApproach() {
  // the sindresorhus approach

  function* play() {
    let h = {};
    input.map((i) => (h[i] = i));
    h = Object.keys(h).map((i) => parseInt(i));
    yield `unique elements size is ${h.length}, and elements are ${h}`;
    for (let i = 0; i < h.length; i++) {
      yield h[getRandomIndex(h.length)()];
    }
  }

  // inspired by https://github.com/sindresorhus/unique-random/blob/main/index.js
  function getRandomIndex(size) {
    let previous;

    return function () {
      const number = Math.floor(Math.random() * size);
      previous = number === previous ? getRandomIndex(size) : number;
      return previous;
    };
  }

  const iterator = play();
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
  console.log(iterator.next().value);
})();

It doesn't guarantee non-duplication beyond the immediate next iteration, however. i.e. in this approach, two subsequent elements won't be duplicates, but if you iterate further, you may encounter some.