Passing $this to a sub-function

[NotionCommotion]

Is it generally considered good practice to explicitly pass $this arguments to sub-functions, or is it okay for the sub-function to directly get the value from $this?  At least today, updateDB() will only use $this->id.

class foo
{
    private $id;
    public function __construct($id)
    {
        $this->id=$id;
    }
    
    public function updateValue($value)
    {
        // ...
        $this->updateDB($value,$this->id);
        // ...
    }

    private function updateDB($value,$id)
    {
        // Or should I just use $this->id?
    }
}  

[Psycho]

They are not 'sub-functions', they are methods within a class. And the variables defined for the class (such as $id) are properties. One of the benefits/reasons for having properties is so that you do not need to pass them between methods because they can be directly accessed via $this. And, passing $this from one method to another could only cause problems that I can see.

 

So, remove $id from the parameter list for the updateValue() method and reference it via $this->id. But, if you have any reason to call updateValue() and pass arbitrary id values, then you could make it an optional parameter. If no value passed used $this->id, else use the passed value.

[NotionCommotion]

Sorry for my poor choice of words for "sub-functions".  I was trying to imply that these were only used to support another method.  I'll go with your optional parameter approach if I think it will be necessary to accept arbitrary IDs.