What are the differences among initialize(), constructor and early options?

Hi,
Sorry if the title is confusing, but looking at the documentation I got wondering. How are they different?

PHP Code:

class UserModel extends UserAuthModel
{
    /**
    * Called during initialization. Appends
    * our custom field to the module's model.
    */
    protected function initialize()
    {
        $this->allowedFields[] = 'middlename';
    }
} 


PHP Code:

class UserModel extends UserAuthModel
{
    protected $allowedFields = 'middlename';
} 


PHP Code:

class UserModel extends UserAuthModel
{
    public function __construct()
    {
        $this->allowedFields[] = 'middlename';
    }
} 


Don't they all execute the code first thing when the class is initiated?
Thanks

This is wrong usage. The model does not work fine. See the BaseModel::__constuct().

PHP Code:

class UserModel extends UserAuthModel
{
    public function __construct()
    {
        $this->allowedFields[] = 'middlename';
    }
} 


The initialize() is a method called at the end of the constructor.
You can write initialization code in it.

ci-phpunit-test | CodeIgniter Testing Guide | CodeIgniter 3 to 4 Upgrade Helper

The intent of the initialize method in the Controller was solely to free up the constructor for your own usage as a developer without having to worry about the class dependencies. My advise - use class vars or the constructor and ignore the initialize method whenever possible.

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