Several methods of JS array de-weight

1Array.prototype.unique1 =function () {2   varn = [];//a new temporary array3    for(vari = 0; I < This. length; i++)//iterate through the current array4   {5     //if the current array of I has been saved into a temporary array, then skip,6     //Otherwise push the current item to the temporary array7     if(N.indexof ( This[i]) = =-1) n.push ( This[i]);8   }9   returnN;Ten }; One  A  -Array.prototype.unique2 =function() - { the     varn = {},r=[];//n is a hash table and r is a temporary array -      for(vari = 0; I < This. length; i++)//iterate through the current array -     { -         if(!n[ This[i]])//If there is no current item in the hash table +         { -n[ This[i]] =true;//Deposit Hash Table +R.push ( This[i]);//Push the current item of the current array into the temporary array A         } at     } -     returnR; - }; -  -  -Array.prototype.unique3 =function() in { -     varn = [ This[0]];//result Array to      for(vari = 1; I < This. length; i++)//start traversing from the second item +     { -         //if the item I of the current array first appears in the current array, the position is not I, the         //then it means that item I is repeated and ignored. Otherwise, the result array is stored *         if( This. IndexOf ( This[i]) = = i) N.push ( This[i]); $     }Panax Notoginseng     returnN; - }; the  +  AArray.prototype.unique4 =function() the { +      This. Sort (); -     varre=[ This[0]]; $      for(vari = 1; I < This. length; i++) $     { -         if( This[i]!== re[re.length-1]) -         { theRe.push ( This[i]); -         }Wuyi     } the     returnre; - }; Wu  -  About vararr = [1,2,2,2,3,3,4,5]; $Console.log (Arr.unique1 ());//[1, 2, 3, 4, 5] -Console.log (Arr.unique2 ());//[1, 2, 3, 4, 5] -Console.log (Arr.unique3 ());//[1, 2, 3, 4, 5] -Console.log (Arr.unique4 ());//[1, 2, 3, 4, 5]

Several methods of JS array de-weight