تحويل العناصر وفرد النتائج بإستخدام flatMap

<?php

$users = collect([["skills" => ["HTML", "CSS"]], ["skills" => ["PHP"]]]);
echo $users->flatMap(fn ($user) => $user["skills"])->toJson();

["HTML","CSS","PHP"]

<?php

$numbers = collect([1, 2, 3]);
echo $numbers->flatMap(fn ($number) => $number > 1 ? [$number, $number * 10] : [])->toJson();

[2,20,3,30]