JavaScript and PHP handle arrays differently

To understand this family of problems, you must first understand how PHP and JavaScript handle arrays:

In PHP, arrays can have numeric or string keys. In JS, arrays can only have numeric keys, and instead, you would use an object for string keys.

Let's take a look at what happens if we convert different PHP arrays to JSON and parse them into JavaScript:

Numeric Ordered Array

PHP	JS
[ 0 => 'foo', 1 => 'bar', 2 => 'baz', ]	[ 0: 'foo', 1: 'bar', 2: 'baz', ]

Numeric Ordered Array

PHP	JS
[ 0 => 'foo', 1 => 'bar', 2 => 'baz', ]	[ 0: 'foo', 1: 'bar', 2: 'baz', ]