optional.php

<?php

// User 1 exists, with account
$user1 = User::find(1);
$accountId = $user1->account->id; // 123

// User 2 exists, without account
$user2 = User::find(2);
$accountId = $user2->account->id; // PHP Error: Trying to get property of non-object

// Fix without optional()
$accountId = $user2->account ? $user2->account->id : null; // null
$accountId = $user2->account->id ?? null; // null

// Fix with optional()
$accountId = optional($user2->account)->id; // null