js数组去重的几种方法

   var arr = [42123,123,3214,123,12321,123,131,1232,2,21,21,3132,2,312,3];//验证时请把其他方法注释起来
    way1
    for(var i = 0;i < arr.length-1;i++){
        for(var j = i+1;j < arr.length;j++){
            if(arr[i] == arr[j]){
                arr.splice(j,1);
                j--;
            }
        }
    }
    
    console.log(arr)
    way2
    for(var i = 0;i < arr.length;i++){
        if(arr.indexOf(arr[i]) != i){
            arr.splice(i,1);
            i--;
        }
    }
    console.log(arr)
    way3
    var srr1 = arr.filter(function(value,index,self){
        return self.indexOf(value) === index
    })
    console.log(srr1)
    console.log(arr)
    way4
    var arr2 = [];
    for(var i = 0;i < arr.length;i++){
        if(arr.indexOf(arr[i]) == i){
            arr2.push(arr[i]);
        }
    }
    console.log(arr2)
    way5
    var obj = {};
    var arr2 = [];
    for(var i = 0;i < arr.length;i++){
        if(!obj[arr[i]]){
            obj[arr[i]] = true;
            arr2.push(arr[i]);
        }
    }
    console.log(arr2)
    way6
    var arr2 = [];
    for(var i = 0; i < arr.length;i++){
        if(arr2.indexOf(arr[i]) == -1){
            arr2.push(arr[i]);
        }
    }
    console.log(arr2)
    way7
    var arr2 = new Set(arr);
    console.log(arr2) //arr2是对象
    var arr2 = [];
    for(var i = 0;i < arr.length;i++){
        var arr3 = [];
        for(var j = i+1;j < arr.length;j++){
            if(arr[i] == arr[j]){
                arr3.push(j);
            }
        }
        if(arr3.length == 0){
            arr2.push(arr[i]);
        }
    }
    console.log(arr2)
    way8
    for(var i = 0;i < arr.length;i++){
        for(var j = i+1;j < arr.length;j++){
            if(arr[i] == arr[j]&&i != j){
                arr.splice(j,1);
            }
        }
        
    }
    console.log(arr)

 

来源：https://www.cnblogs.com/stdzz/p/11561322.html