dedupe arrays in javascript

dedupe.js

// deduplicate array of primitives
let deduped = arr.filter((el, i, arr) => arr.indexOf(el) === i);
// or
deduped = Array.from(new Set(arr));

// deduplicate array of ojects using a hash table
function dedupe(arr) {
  let hashTable = {};
  
  return arr.filter(function(el) {
    let key = JSON.stringify(el); // or JSON.stringify(el.prop)
    let match = Boolean(hashTable[key]);
    return (match ? false : hashTable[key] = true);
  });
}

deduped = dedupe(arr);