Optionally pass through a single view parameter in Laravel 5 - php

Question

Consider this scenario where I want to SOMETIMES pass data through to my view:
public function show($orderId)
{
if ($sometimesTrue == true)
{
$optionalParameter = 'optional parameter';
}
return view('show', compact([$a, $b, $c, $optionalParameter]));
}
$optionalParameter is not always set, so I want to know what my options are for setting individual, optional view parameters without re-arranging the structure of the function.
In Zend, the following is possible:
$this->view->optionalParameter = $optionalParameter;
Which can go anywhere in the controller method, not just at the end where the view is instantiated. Of course, back in Laravel, I could do something this:
public function show($orderId)
{
$paramaterArray = [$a, $b, $c];
if ($sometimesTrue == true)
{
$optionalParameter = 'optional parameter';
$paramaterArray[] = $optionalParameter;
}
return view('show', compact($paramaterArray));
}
But re-arranging entire functions because a optional parameter is introduced seems a bit limiting. Is there any way I can set an individual parameter for a view?

Answer 1

You can just built your own protected function + protected property in the Controller class. You could do something like this:
Beneath is using the splat operator so it will only work in php 5.6 >=
protected $optionalParameter;
protected function optionalcompact(...$parameters) {
if(!empty($this->optionalParameter)){
return compact($parameters, $this->optionalParameter);
} else {
return compact($parameters);
}
}
Then back in your own built controller class you can do this:
public function show($orderId)
{
if ($sometimesTrue == true)
{
$this->optionalParameter = 'optional parameter';
}
return view('show', $this->optionalcompact($a, $b, $c));
}

Answer 2

I would simply use the following
public function show($orderId)
{
$paramaterArray = [$a, $b, $c];
$paramaterArray['optional'] = $sometimesTrue == true ? 'optional parameter' : '';
return view('show', $paramaterArray);
}
Since this is an optional parameter so I don't need to check every time in my view whether it's set or not, simply {{ $optional }} will work better, it'll be printed if any value is set or nothing will be printed if the $optional variable is empty. This way, I'll remain consistant.
Also, you may check the Larave's View Composers, it may help you.

Answer 3

Researching further, it seems that using compact with the names of the variables (as opposed to the variables themselves) will silently ignore the missing variable which gives the intended behaviour:
$var1 = 'bob';
$var2 = 'nigel';
var_dump(compact('var1', 'var2', 'var3'));
Returns:
array(2) { ["var1"]=> string(3) "bob" ["var2"]=> string(5) "nigel" }
Which works perfectly for my scenario. Using it this way, the controller method doesn't require refactoring and no additional coding is required. Whether relying on compact to not issue a warning is good coding practice is another question.
Just to confirm, calling compact with the variables themselves WILL throw a notice warning:
$var1 = 'bob';
$var2 = 'nigel';
var_dump(compact($var1, $var2, $var3));
Returns:
NOTICE Undefined variable: var3 on line number 4