PHP's array_pop in JavaScript

Here’s what our current JavaScript equivalent to PHP's array_pop looks like.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
module.exports = function array_pop (inputArr) { // eslint-disable-line camelcase
// discuss at: http://locutus.io/php/array_pop/
// original by: Kevin van Zonneveld (http://kvz.io)
// improved by: Kevin van Zonneveld (http://kvz.io)
// input by: Brett Zamir (http://brett-zamir.me)
// input by: Theriault (https://github.com/Theriault)
// bugfixed by: Kevin van Zonneveld (http://kvz.io)
// bugfixed by: Brett Zamir (http://brett-zamir.me)
// note 1: While IE (and other browsers) support iterating an object's
// note 1: own properties in order, if one attempts to add back properties
// note 1: in IE, they may end up in their former position due to their position
// note 1: being retained. So use of this function with "associative arrays"
// note 1: (objects) may lead to unexpected behavior in an IE environment if
// note 1: you add back properties with the same keys that you removed
// example 1: array_pop([0,1,2])
// returns 1: 2
// example 2: var $data = {firstName: 'Kevin', surName: 'van Zonneveld'}
// example 2: var $lastElem = array_pop($data)
// example 2: var $result = $data
// returns 2: {firstName: 'Kevin'}
var key = ''
var lastKey = ''
if (inputArr.hasOwnProperty('length')) {
// Indexed
if (!inputArr.length) {
// Done popping, are we?
return null
}
return inputArr.pop()
} else {
// Associative
for (key in inputArr) {
if (inputArr.hasOwnProperty(key)) {
lastKey = key
}
}
if (lastKey) {
var tmp = inputArr[lastKey]
delete (inputArr[lastKey])
return tmp
} else {
return null
}
}
}
[ View on GitHub | Edit on GitHub | Source on GitHub ]

How to use

You you can install via npm install locutus and require it via require('locutus/php/array/array_pop'). You could also require the array module in full so that you could access array.array_pop instead.

If you intend to target the browser, you can then use a module bundler such as Browserify, webpack or rollup.js.

ES5/ES6

This function targets ES5, but as of Locutus 2.0.2 we also support ES6 functions. Locutus transpiles to ES5 before publishing to npm.

PHP arrays and JavaScript

Please note that Locutus uses JavaScript objects as substitutes for PHP arrays, they are the closest we can get to this hashtable-like data structure without rolling our own. While many JavaScript implementations preserve the order of object properties, the ECMAScript Language Specification explicitly states that:

The mechanics and order of enumerating the properties is not specified.

So don't use this for anything serious if you rely on the order to be consistent accross platforms.

A community effort

Not unlike Wikipedia, Locutus is an ongoing community effort. Our philosophy follows The McDonald’s Theory. This means that we don't consider it to be a bad thing that many of our functions are first iterations, which may still have their fair share of issues. We hope that these flaws will inspire others to come up with better ideas.

This way of working also means that we don't offer any production guarantees, and recommend to use Locutus inspiration and learning purposes only.

Notes

  • While IE (and other browsers) support iterating an object’s own properties in order, if one attempts to add back properties in IE, they may end up in their former position due to their position being retained. So use of this function with “associative arrays” (objects) may lead to unexpected behavior in an IE environment if you add back properties with the same keys that you removed

Examples

Please note that these examples are distilled from test cases that automatically verify our functions still work correctly. This could explain some quirky ones.

#codeexpected result
1array_pop([0,1,2])2
2var $data = {firstName: 'Kevin', surName: 'van Zonneveld'} var $lastElem = array_pop($data) var $result = $data{firstName: 'Kevin'}

« More PHP array functions