Several methods for array de-weight-------javascript description

1. The first method: the use of JSON objects, if no JSON object is added, otherwise not added, and finally return the properties of the JSON object, the time complexity of O (n)

 function   deletearrayrepeat (arr) {        var  result = {};         var  temp = [];  //  for  (var  i = 0; i < arr.length; i++ if  (! = 0; 
            Temp.push (arr[i]);    }}  return   temp; }

2. The second method uses the filter () method and the IndexOf () method. Because the filter method and the IndexOf method are essentially a layer for loop implementation, The time complexity is O (n*n); the code is as follows

function deletearrayrepeat (arr) {        return arr.filter (function(item,i) {              return arr.indexof (item) = = =i;        }    );

3.3rd method: using the indexof () method, the time complexity is O (n*n);

function deletearrayrepeat (arr) {        var temp=[];          for (var i=0;i<arr.length;i++) {            if(temp.indexof (arr[i]) ===-1) {                Temp.push (arr[i]);            }        }         return temp;    }

Several methods for array de-weight-------javascript description