How to pass data to view only if it is defined? - php

Question

As you can see in my piece of code below, $similarImages is being passed to the view, however, it is possible that there are no other similar images which means I'll pass an undefined variable. This is why I need to pass 'similarImages' => $similarImages only if $similarImages exists.
$tag = Tag::whereHas('images', function($q) use ($id) {
return $q->where('image_id', $id);
})->first();
if (!empty($tag)) {
$tagId = $tag->id;
}
$recentImages = Image::where('user_id', $authorId)->orderBy('created_at', 'desc')->limit(9)->get();
if (!empty($tagId)) {
$similarImages = Image::whereHas('tags', function($q) use ($tagId) {
return $q->where('tag_id', $tagId);
})->orderBy('created_at', 'desc')->limit(9)->get();
}
return view('specificImage', ['image' => $image, 'recentImages' => $recentImages, 'similarImages' => $similarImages, 'author' => $author, 'comments' => $comments]);

Answer 1

Make use of the null-coalescing operator to have a default value:
[ .. 'similarImages' => $similarImages ?? collect(), .. ]
This will use $similarImages if it is defined and not null otherwise it will assign an empty collection created by collect().
I like the idea of it always being a collection, but that's just me.

Answer 2

$array is always pass to the view
and if isset $similarImages, just prepend the $similarImages into $array
if not isset $similarImages just return $array (in this case $similarImages won't exists in blade)
here also you can use array_add($array, 'similarImages', $similarImages)
$tag = Tag::whereHas('images', function($q) use ($id) {
return $q->where('image_id', $id);
})->first();
if (!empty($tag)) {
$tagId = $tag->id;
}
$recentImages = Image::where('user_id', $authorId)->orderBy('created_at', 'desc')->limit(9)->get();
if (!empty($tagId)) {
$similarImages = Image::whereHas('tags', function($q) use ($tagId) {
return $q->where('tag_id', $tagId);
})->orderBy('created_at', 'desc')->limit(9)->get();
}
$array = [
'image' => $image,
'recentImages' => $recentImages,
'author' => $author,
'comments' => $comments
];
if (isset($similarImages))
{
$array = array_prepend($array, $similarImages, 'similarImages')
}
return view('specificImage', $array);