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Get the last item in an array


Question

Here is my JavaScript code so far:

var linkElement = document.getElementById("BackButton");
var loc_array = document.location.href.split('/');
var newT = document.createTextNode(unescape(capWords(loc_array[loc_array.length-2]))); 
linkElement.appendChild(newT);

Currently it takes the second to last item in the array from the URL. However, I want to do a check for the last item in the array to be "index.html" and if so, grab the third to last item instead.

2020/05/16
1
1211
5/16/2020 3:52:55 PM

Accepted Answer

if (loc_array[loc_array.length - 1] === 'index.html') {
   // do something
} else {
   // something else
}

In the event that your server serves the same file for "index.html" and "inDEX.htML" you can also use: .toLowerCase().

Though, you might want to consider doing this server-side if possible: it will be cleaner and work for people without JS.

2020/03/23
1295
3/23/2020 6:38:42 PM


Use Array.pop:

var lastItem = anArray.pop();

Important : This returns the last element and removes it from the array

2014/09/03

A shorter version of what @chaiguy posted:

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

Reading the -1 index returns undefined already.

EDIT:

These days the preference seems to be using modules and to avoid touching the prototype or using a global namespace.

export function last(array) {
    return array[array.length - 1];
}
2018/09/20

Two options are:

var last = arr[arr.length - 1]

or

var last = arr.slice(-1)[0]

The former is faster, but the latter looks nicer

http://jsperf.com/slice-vs-length-1-arr

2014/06/18

Here's how to get it with no effect on the original ARRAY

a = [1,2,5,6,1,874,98,"abc"];
a.length; //returns 8 elements

If you use pop(), it will modify your array

a.pop();  // will return "abc" AND REMOVES IT from the array 
a.length; // returns 7

But you can use this so it has no effect on the original array:

a.slice(-1).pop(); // will return "abc" won't do modify the array 
                   // because slice creates a new array object 
a.length;          // returns 8; no modification and you've got you last element 
2015/10/24

The "cleanest" ES6 way (IMO) would be:

const foo = [1,2,3,4];
const bar = [...foo].pop();

This avoids mutating foo, as .pop() would had, if we didn't used the spread operator.
That said, I like aswell the foo.slice(-1)[0] solution.

2018/10/29

Source: https://stackoverflow.com/questions/3216013
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