ES6数组去重的5种方法是什么

let arr=[1,2,3,3,2,"1",0,undefined,undefined];
let newArr=Array.from(new Set(arr));
console.log(newArr);

let arr=[1,2,3,3,2,"1",0,1,2];
let newArr=[...new Set(arr)];
console.log(newArr);

var arr=[1,2,3,3,2,"1",0,1,2,undefined,undefined];
var newArr = [];
for(let i = 0;i <arr.length;i++){
    if(newArr.indexOf(arr[i]) ===-1) {
      newArr.push(arr[i]);
    }
}
console.log(newArr);

var arr=[1,2,3,3,2,"1",0,1,2,undefined,undefined];
var newArr = [];
for(let i = 0;i <arr.length;i++){
  if(!newArr.includes(arr[i])){
    newArr.push(arr[i]);
  }
}
console.log(newArr);

var arr=[1,2,3,3,2,"1",0,1,2,undefined,undefined];
var newArr = arr.filter((item,index)=> {
  return arr.indexOf(item,0) === index;
});
console.log(newArr);