es6高效数组去重方式set map数组去重，保留数组去重最快的方式，用到set和map es6的方法，也是最为简介的方

个人仅以此为记录

set

Array.prototype.unique = function () {
  return [...new Set(this)];
}

const uniqueArr = (arr) => [...new Set(arr)];

console.log(uniqueArr(["前端","js","html","js","css","html"]));
// ['前端', 'js', 'html', 'css']

map

 Array.prototype.unique = function () {
  const tmp = new Map();
  return this.filter(item => {
    return !tmp.has(item) && tmp.set(item, 1);
  })
}