unique.js

/**
 * Remove all duplicate items from array
 *
 * @param {Array} array input array
 * @returns {Array} an array of unique values
 *
 */

function unique (array) {
  return [...array.reduce((acc, curr) => {
    acc.add(curr);
    return acc;
  }, new Set())];
}

/**
 * example below
 */
const result = unique([2, 1, 2]);

console.log(result);

// [2, 1]