JS数组去重

let arr = [2,14,24,10,11,15,14,2] ;
function removal(arr) {  
  let hashTable = {};
  let data = [];
  for(let i=0,l=arr.length;i<l;i++) {
    if(!hashTable[arr[i]]) {
      hashTable[arr[i]] = true;
      data.push(arr[i]);
    }
  }
  return data
}
removal(arr)  //[2, 14, 24, 10, 11, 15]