PHP's array_is_list() is underrated

Before PHP 8.1 I kept writing little helpers to check whether an array was a “real” list (keys 0..n-1, in order) or an associative map. Turns out the language ships it now:

array_is_list([1, 2, 3]);        // true
array_is_list([1 => 'a']);       // false
array_is_list(['a' => 1]);       // false

Handy when you’re normalising JSON input or deciding whether to encode something as a JSON array vs object. One less utility to maintain.