Why doesn t JavaScript have a last method

Question

Its kinda weird that the JavaScript Array class does not offer a last method to retrieve the last element of an array  I know the solution is simple  Ar Ar length-1     but  still  this is too frequently used   Any serious reasons why this is not incorporated yet

User · Answer

You can do something like this    10  20  30  40  slice -1  0     x000D   x000D  console log  10  20  30  40  slice -1  0   x000D   x000D   x000D    The amount of helper methods that can be added to a language is infinite  I suppose they just haven t considered adding this one

User · Answer

Here is another simpler way to slice last elements   var tags    1  2  3   foo    bar    foobar    barfoo     var lastObj   tags slice -1     lastObj is now   barfoo     Python does this the same way and when I tried using JS it worked out  I am guessing string manipulation in scripting languages work the same way   Similarly  if you want the last two objects in a array   var lastTwoObj   tags slice -2    will give you   foobar    barfoo   and so on

User · Answer

pop   method will pop the last value out  But the problem is that you will lose the last value in the array

User · Answer

Because Javascript changes very slowly  And that s because people upgrade browsers slowly   Many Javascript libraries implement their own last   function  Use one

User · Answer

Came here looking for an answer to this question myself  The slice answer is probably best  but I went ahead and created a  last  function just to practice extending prototypes  so I thought I would go ahead and share it  It has the added benefit over some other ones of letting you optionally count backwards through the array  and pull out  say  the second to last or third to last item  If you don t specify a count it just defaults to 1 and pulls out the last item   Array prototype last   Array prototype last    function count        count   count    1      var length   this length      if  count  lt   length            return this length - count         else           return null            var arr    1  2  3  4  5  6  7  8  9   arr last       returns 9 arr last 4      returns 6 arr last 9      returns 1 arr last 10      returns null

User · Answer

i      concat loves  pop      corn   icon cat loves popcorn

User · Answer

It s easy to define one yourself  That s the power of JavaScript   if  Array prototype last        Array prototype last   function             return this this length - 1            var arr    1  2  5   arr last       5   However  this may cause problems with 3rd-party code which  incorrectly  uses for  in loops to iterate over arrays   However  if you are not bound with browser support problems  then using the new ES5 syntax to define properties can solve that issue  by making the function non-enumerable  like so   Object defineProperty Array prototype   last         enumerable  false      configurable  true      get  function             return this this length - 1              set  undefined      var arr    1  2  5   arr last     5

User · Answer

Yeah  or just    var arr    1  2  5   arr reverse   0    if you want the value  and not a new list

User · Answer

Array prototype last   Array prototype last    function         var l   this length      return this l-1      x    1 2   alert  x last

User · Answer

Another option  especially if you re already using UnderscoreJS  would be     last  1  2  3  4       Will return 4

[javascript] Why doesn't JavaScript have a last method?

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