数组值只包含了字符和数字，更多范例增添不会影响以下method_*的排序(时候排序)

测试环境：版本 57.0.2987.133 (64-bit)

var arr1 = [1, 1, 2, 2, 3, 4, 4, 5, 5, 6, 1, 2, 3, 4, 5, 6, "1", "2", "1", "2"];
var arr2 = [1, 1, 2, 2, 3, 4, 4, 5, 5, 6, 1, 2, 3, 4, 5, 6];

while(arr1.length < 600000){

    arr1 = arr1.concat(arr1);
    arr2 = arr2.concat(arr2);
}

// 
// 
// 
// method_1：新建数组-双轮回-对照-push
Array.prototype.unique = function(){

    var res = [this[0]],
        len = this.length;

    for(var i = 1; i < len; i ++){

        var repeat = false,
            rlen     = res.length;

        for (var j = 0; j < rlen; j ++){

            if(this[i] === res[j]){

                repeat = true;
                break;
            }
        }

        !repeat && res.push(this[i]);
    }

    return res;
}

var timestamp = new Date().getTime();
arr1 = arr1.unique();
console.log(new Date().getTime() - timestamp); // 均匀 18

var timestamp = new Date().getTime();
arr2 = arr2.unique();
console.log(new Date().getTime() - timestamp); // 均匀 10

// 
// 
// 
// method_2：新建数组-排序-单轮回-对照-push
Array.prototype.unique = function () {
 
    this.sort(function (a, b) {
     
        if (typeof a != typeof b && a == b) {
     
            if (typeof a == "number") {
                return -1;
            } else {
                return 1
            }
        }
        return parseInt(a) - parseInt(b);
    })

    var res = [this[0]],
        len = this.length;

    for (var i = 1; i < len; i ++) {

        var slen = res.length;


        if (this[i] !== res[slen -1]) {

            res.push(this[i]);
        }
    }

    return res;
}

var timestamp = new Date().getTime();
arr1 = arr1.unique();
console.log(new Date().getTime() - timestamp); // 均匀 121

var timestamp = new Date().getTime();
arr2 = arr2.unique();
console.log(new Date().getTime() - timestamp); // 均匀 93

// 
// 
// 
// method_3：新建数组-新建对象-单轮回-对象对照-数组push 
Array.prototype.unique = function () {

    var res = [],
        obj = {},
        len = this.length;

    for (var i = 0; i < len; i++) {

        // 因为对象属性为字符串 1 和 "1" 雷同，因而做不到 ===
        !obj[this[i]] && res.push(this[i]) && (obj[this[i]] = 1);

    }
    return res;
}
var timestamp = new Date().getTime();
arr1 = arr1.unique();
console.log(new Date().getTime() - timestamp); // 均匀 8

var timestamp = new Date().getTime();
arr2 = arr2.unique();
console.log(new Date().getTime() - timestamp); // 均匀 5

// 
// 
// method_4：新建数组-轮回-向后查询-数组push
Array.prototype.unique = function () {
 
    var res = [],
        len = this.length,
        i, j;
    for (i = 0; i < len; i++) {

        for (j = i + 1; j < len; j++) {

            if (this[i] === this[j]) {

                j = false;
                break;
            }
        }
        
        j && res.push(this[i]);
    }
    
    return res;
}
var timestamp = new Date().getTime();
arr1 = arr1.unique();
console.log(new Date().getTime() - timestamp); // 均匀 28

var timestamp = new Date().getTime();
arr2 = arr2.unique();
console.log(new Date().getTime() - timestamp); // 均匀 17

// 
// 
// 
// method_4：运用Set
Array.prototype.unique = function (){

    var arr = new Set(this);

    return [...arr];
}
var timestamp = new Date().getTime();
arr1 = arr1.unique();
console.log(new Date().getTime() - timestamp); // 均匀 75

var timestamp = new Date().getTime();
arr2 = arr2.unique();
console.log(new Date().getTime() - timestamp); // 均匀 60

// 
// 
// 
// method_5：运用find/findIndex/indexOf
Array.prototype.unique = function(){

    var res = [this[0]],
        len = this.length;

    for(var i = 1; i < len; i ++){

        var repeat = false,
            rlen     = res.length;

        if(!res.find((v,k)=>{return v === this[i]})){
            
            res.push(this[i]);
        }

        // if(res.indexOf(this[i]) == -1){

        //     res.push(this[i]);   
        // }

        // if(res.findIndex((v,k)=>{return v === this[i]}) == -1){
            
        //     res.push(this[i]);
        // }
    }

    return res;
}
var timestamp = new Date().getTime();
arr1 = arr1.unique();
console.log(new Date().getTime() - timestamp); // 均匀 110+

var timestamp = new Date().getTime();
arr2 = arr2.unique();
console.log(new Date().getTime() - timestamp); // 均匀 65+

总结

method_1时候为 18 /10 ，轮回对照。

method_2时候为 121/93 , 假如依靠sort排序(在字符和数字组合中更是依靠sort callback)大大增添的时候，而且影响了原有数组递次。

method_3时候为 8/5 , 没法辨别字符和数字。

method_4时候为 28/7 ，同method_1为轮回对照，然则增添了内层轮回次数。

method_5时候为 75/60 , 运用Set数据结构特征。

method_5时候为 110+/65+ , 运用find/findIndex/indexOf推断。

整体来讲最好挑选为 method_1

然则引荐运用method_5—-大道至简