last element of array in javascript

Question

Its kinda weird Javascript Array class does not offer last method to retrieve the last element of array. I know the solution is too simple (Ar[Ar.length-1] ) but still this is too frequently used.

Any serious reasons why this is not incorporated yet?

Answer 1

It's easy to define one yourselves. That's the powa of JavaScript.

if(!Array.prototype.last) {
    Array.prototype.last = function() {
        return this[this.length - 1];
    }
}

var arr = [1, 2, 5];
arr.last(); // 5

Or if you are not bound with browser support problems, then use the new ES5 syntax to define properties. Chrome and Firefox nightly only at the moment.

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

Answer 2

Because Javascript changes very slowly. And that's because people upgrade browsers slowly.

Many Javascript libraries implement their own last() function. Use one!

Answer 3

Array.prototype.last = Array.prototype.last || function() {
    var l = this.length;
    return this[l-1];
}

x = [1,2];
alert( x.last() )

Answer 4

You can do something like this:

[10, 20, 30, 40].slice(-1)[0]

The amount of helper methods that can be added to a language is close to infinity. I suppose they just haven't considered adding this one.