dompdf stream not working - laravel

I use barryvdh/laravel-dompdf in laravel 5.4 on chrome. when I try to stream. it always return download Even though I was passing only the HTML from route

Route::get('hellopdf', function(){
     return PDF::loadHTML('Hello World!')->stream('download.pdf');
});

but still it ended up with download not open new tab then review.btw I've used <a href target"_blank">

here's my controller

public function PDFpurchasetrans($id)
    {
        $purchase = Purchase::find($id);
        $data = App\PurchaseDetail::where('purchase_id', $id)->get();
        $pdf = PDF::loadView('purchases.pdftrans', compact('data', 'purchase'));
        $pdf->setPaper([0, 0, 684, 792], 'potrait');
        return $pdf->stream('struk-pembelian' . date('Y-m-d H:i:s') . '.pdf');
    }

via Chebli Mohamed