Pinned Loading

1. 단순 배열 중복 제거 단순 배열 중복 제거

   1

   let arr = [1,2,3,12,312,312,3,21,1,2,3,12,312,1,2,3,1,2,3,1];

   2

   [...new Set(arr)];

   3

   // output => [1,2,3,12,312,21]