js数组去重方法（处理{}和NaN结果不同）

1、利用es6中set唯一(不能去掉重复的{})

[].from(new Set([1,1,'true','true',true,true,15,15,false,false, undefined,undefined, null,null, NaN, NaN,'NaN', 0, 0, 'a', 'a',{},{}]));
[...new Set([1,1,'true','true',true,true,15,15,false,false, undefined,undefined, null,null, NaN, NaN,'NaN', 0, 0, 'a', 'a',{},{}])]
//[1, "true", true, 15, false, undefined, null, NaN, "NaN", 0, "a", {}, {}]  length:13

2、es5的Array filter()+indexOf() (不能去掉重复的{})

[1,1,'true','true',true,true,15,15,false,false, undefined,undefined, null,null, NaN, NaN,'NaN', 0, 0, 'a', 'a',{},{}].filter(function(elem,index,Array){
   return index === Array.indexOf(elem);
})
//[1, "true", true, 15, false, undefined, null, NaN, "NaN", 0, "a", {}, {}]  length:13

3、基础写法1(不能过滤NaN和{})

function unique(arr){
    var res=[];
    for(var i=0,len=arr.length;i<len;i++){
        var obj = arr[i];
        for(var j=0,jlen = res.length;j<jlen;j++){
            if(res[j]===obj) break;            
        }
        if(jlen===j)res.push(obj);
    }
    return res;
}
var arr=[1,1,'true','true',true,true,15,15,false,false, undefined,undefined, null,null, NaN, NaN,'NaN', 0, 0, 'a', 'a',{},{}];
var ary = unique(arr);
console.log(ary)//[1, "true", true, 15, false, undefined, null, NaN, NaN, "NaN", 0, "a", {…}, {…}] length:14

4、基础写法2(不能过滤NaN和{})

function unique(arr){
    for(var i=0;i<arr.length;i++){
        for(var j=i+1;j<arr.length;j++){
            if(arr[i]==arr[j]){
              arr.splice(j,1);
              j--;
            }
        }
    }
    return arr;
}
var arr = [1,1,'true','true',true,true,15,15,false,false, undefined,undefined, null,null, NaN, NaN,'NaN', 0, 0, 'a', 'a',{},{}];
var ary = unique(arr);
console.log(ary)//[1, "true", true, 15, false, undefined, null, NaN, NaN, "NaN", 0, "a", {…}, {…}] length:14

5、利用{}的key唯一性 (能过滤{}，但不能区分“NaN”和NaN)

function unique(arr) {
  var obj= {};
  return arr.filter(function(elem) {
    return obj.hasOwnProperty(elem) ? false : (obj[elem] = true);//
  });
}
var arr = [1,1,'true','true',true,true,15,15,false,false, undefined,undefined, null,null, NaN, NaN,'NaN', 0, 0, 'a', 'a',{},{}];
var ary= unique(arr);
console.log(ary); //[1, "true", 15, false, undefined, null, NaN, 0, "a", {…}]  length:10

6、利用map的key唯一性 (不能去掉重复的{})

function unique(arr){
  let ary=[]
  let map=new Map()
  for(let i=0;i<arr.length;i++){
    if(!map.get(arr[i])){
      map.set(arr[i],1)
      ary.push(arr[i])
    }
  }
  return ary
}
var arr = [1,1,'true','true',true,true,15,15,false,false, undefined,undefined, null,null, NaN, NaN,'NaN', 0, 0, 'a', 'a',{},{}];
var ary= unique(arr);
console.log(ary); //[1, "true", true, 15, false, undefined, null, NaN, "NaN", 0, "a", {}, {}]   length:13

7、利用reduce和includes (不能去掉重复的{})

function unique(arr){
    return arr.reduce((prev,cur) => prev.includes(cur) ? prev : [...prev,cur],[]);
}
var arr = [1,1,'true','true',true,true,15,15,false,false, undefined,undefined, null,null, NaN, NaN,'NaN', 0, 0, 'a', 'a',{},{}];
console.log(unique(arr));//[1, "true", true, 15, false, undefined, null, NaN, "NaN", 0, "a", {}, {}]   length:13