Pagination with dinamic data.

Can you show your code, please?

Migration:

public function up()
{
    Schema::create('products', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->unsignedInteger('amount');
        $table->string('name', 30)->nullable();
        $table->enum('type', ['full-price', 'cut-price']);
        $table->timestamps();
    });
}

Controller:

public function index(Product $product, int $page = 1, string $filter = NULL)
{
    if ($filter && !in_array($filter, ['full-price', 'cut-price']))
        $filter = NULL;
    $page = (int)$page ?: 1;

    \Illuminate\Pagination\Paginator::currentPageResolver(function () use ($page) {
        return $page;
    });

    $paginator = $product->AvailableByPage($filter);
    $products['data'] = $paginator->items();
    $products['hasMore'] = $paginator->hasMorePages();
    if($page === 1)
        $products['total'] = $product->AvailableCount($filter);

    return $this->defaultResponse([
        'products' => [
            'items' => $products,
        ]]);
}

Model:

public function AvailableByPage(?string $filter)
{
    return Product::Select('*')
        ->if($filter, 'type', '=', $filter)
        ->where('amount', '>', 0)
        ->orderBy('amount', 'DESC')
        ->withSomethingElse()
        ->simplePaginate($this->items_per_page);
}

P/S its just example.

Have a look at [forPageAfterId()[(https://github.com/laravel/framework/blob/5.5/src/Illuminate/Database/Query/Builder.php#L1549)

MyModel::forPageAfterId($perPage = 15, $lastId = 0, $column = 'id')

Say your first page loads (5 per page) and the IDs are 4, 6, 7, 9 and 12. You click next, but in the last few seconds another user deleted record 7. When you click next you would normally miss the record after 12 (as that now falls on page 1). Instead use forPageAfterId();

$lastId = 12; // last value from previous page
MyModel::select('*')
    ->forPageAfterId(5, $lastId)
    ->get();

Even though there are only 4 items on page 1, you still see the first 5 after the id of 12.

This will only work if paginating on the id column, but the principle is the same. In your code you need to track the last result of the current page (or first if navigating backwards) and whenever you requery add in an extra filter that says "the first X records that meet the criteria but start at X".

We can't use this principle because order column ISN'T unique! I forget add order condition in example sorry.

Your code looks too complicated to me. Why are you creating paginator instance? I would just put a paginator in the controller where I call the model and before I send it to the view like so:

$products = Product::Select('*')
        ->if($filter, 'type', '=', $filter)
        ->where('amount', '>', 0)
        ->orderBy('amount', 'DESC')
        ->withSomethingElse()
        ->simplePaginate($this->items_per_page);

return view('products', compact('products));

and nothing else.

You do not have to handle all paginator stuff since it is done automatically by Laravel.

Hope I got the question right.

Because current page parameter user send with route argument and Paginator dont see it by default. But it doesn't matter since this is not the reason of problem. Route path: xhr/products/page/{page}/{filter?}