laravel collection flatten

$collection = collect(['name' => 'taylor', 'languages' => ['php', 'javascript']]);

$flattened = $collection->flatten();

$flattened->all();

// ['taylor', 'php', 'javascript'];

$collection = collect([1,2,3,4]);

$collection->each(function($item){
    return $item*$item;
});

// [1,4,9,16]