Controller can't return json data

Hello, I'm currently working with the PHP framework Codeigniter 4.0.4 and trying to add the PayPal Checkout Intergration with Smart Payment Buttons.

Console error:

Code:

Uncaught SyntaxError: Unexpected token < in JSON at position 0

Error: Unexpected token < in JSON at position 0
    at $t.error (https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:59754)
    at Object.<anonymous> (https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:67521)
    at JSON.parse (<anonymous>)
    at o (https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:67380)
    at cr (https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:67533)
    at Cr.u.on (https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:72204)
    at Cr (https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:72341)
    at https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:78460
    at Function.n.try (https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:14069)
    at https://www.paypal.com/sdk/js?client-id=Af6lu4xavdi1_e_hEFLWQxUj48hq0bndx7o3RGgwNWuChHmenioXFLMnTOKt912F6zmftF1Siv9WsfCp&disable-funding=credit,card:2:78257

Serverside:

PHP Code:

$clientId = getenv('paypal.CLIENT_ID');
$clientSecret = getenv('paypal.CLIENT_SECRET');

$environment = new SandboxEnvironment($clientId, $clientSecret);
$client = new PayPalHttpClient($environment);

$request = new OrdersCreateRequest();
$request->prefer('return=representation');
$request->body = [
    "intent" => "CAPTURE",
    "purchase_units" => [[
        'reference_id' => '123',
        "amount" => [
            "value" => 10,
            "currency_code" => "USD"
        ]
    ]],
    "application_context" => [
        "cancel_url" => base_url() . "/checkout",
        "return_url" => base_url() . "/checkout"
    ]
];

try {
    $response = $client->execute($request);
    return json_encode($response);
} catch (HttpException $ex) {
    echo $ex->statusCode;
    print_r($ex->getMessage());
} 


Clientside:

PHP Code:

<script type="text/javascript">
    paypal.Buttons({
        env: 'sandbox',

        style: {
            layout: 'vertical',
            size: 'responsive',
            shape: 'pill',
            color: 'blue',
            label: 'pay'
        },

        createOrder: function() {
            return fetch('/checkout/paypal', {
                method: 'post',
                headers: {
                    'content-type': 'application/json'
                }
            }).then(function(response) {
                return response.json();
            }).then(function(resJson) {
                return resJson.result.id;
            });
        }
    }).render('#paypal-button-container');
</script> 


$response outputs the whole page I guess, how I can only return the $response json?

Try to use this (according to documentation):

PHP Code:

return $this->response->setJSON($data);  // $data - is array 


i wanted to implement https://demo.paypal.com/au/demo/download...2&lang=PHP
its is simple PHP solution(it working fine standalone)
i've load constants in my constants file and past the index.php code in my view file and also make a new controller.
when i make the
Error when i click the javascript paypal button
Uncaught SyntaxError: Unexpected token < in JSON at position 0

this error come from this code

return fetch(
'<?=URL['services']['orderCreate']?>',
{
method: 'POST',
body: formData
}
).then(function(response) {
return response.json(); ## PRBLEM with this line JSON return issue
// console.warn(xhr.response.json())
}).then(function(resJson) {
console.log('Order ID: '+ resJson.data.id);
return resJson.data.id;
});
},

i've mention above there is an issue in return response.json();
above plase tell how to get he response in json format.
in CI. i'm using CI 3.x.

maybe you should upgrade to the newest version of CodeIgniter 4.1.1 which has bug fixes.

Also try sending setting a json header to tell it what your sending.

What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )