javascript日志-array数组去重

① array数组去重

    var arr1 = [1,5,5,6,8,8,9];
    function unique (array) {
      var arr2 = [];
      for(var i = 0;i < arr1.length;i++){
        if(arr2.indexOf(arr1[i]) == -1){
          arr2.push(arr1[i]);
        }
      }
      return arr2;
    }
    console.log(unique(arr1)); //[1, 5, 6, 8, 9]

② array以原生链的方式数组去重，按从小到大排序

    var arr1 = [5,5,1,8,8,6,9];
    Array.prototype.unique = function () {
      this.sort();
      var arr2 = [this[0]];
      for(var i=1;i<this.length;i++){
        if(this[i] !== arr2[arr2.length-1]){
          arr2.push(this[i]);
        }
      }
      return arr2;
    }
    console.log(arr1.unique()); //[1, 5, 6, 8, 9]