js 数组去重

/** 
 * 数组去重
 * @param   {Array}		数组 
 * @return  {Array}		去重后的数组
 */ 

var distinct = function(arr){    
    var i = 0, l = arr.length, v, t, o = {}, n = [];    
    for(; i < l; i++){  
        v = arr[i], t = typeof v;    
        if(typeof o[v+t] == 'undefined'){    
            o[v+t] = 1;   
            n.push(v);  
        }   
    }  
    return n;    
};
  
var arr = [1,2,3,4,5,2,1,3,'3',5,6,7,'2',1];    
var newArr = distinct(arr); 
console.log(newArr) // [1, 2, 3, 4, 5, "3", 6, 7, "2"]