In php, I need a function to return all keys in array of objects. For arrays and objects I need keys like parentkey->key.  If the key is again an array, then I need parentkey->key->key1.
My code as below
$array=json_decode('{"client":"4","gateWay":"1","store":"store.shop.com",
"valid":"true","po":34535,"additionalPO":23423,"customerNotes":"",
"orderItems":[{"item":"123","quantity":10,"supplierLotNo":"",
"customsValue":"","customsDescription":"","hsCode":""},
{"item":"345","quantity":50}],
"shippingInfos":[{"address":{"city":"Chennai",
"country":"India","postalCode":"86715","state":"TN",
"streetAddress1":"6971 North Street","streetAddress2":null},
"contact":{"company":null,"email":"[email protected]","firstName":"test",
"lastName":"test","phoneNo":null},"ServiceId":"3","thirdPartyAccountNo":"",
"signatureConfirmation":false,"saturdayDelivery":false}]}',true);
function array_keys_multi(array $array,$headkey,$pkey){
    $keys = array();$hkey='';$parentkey='';
    foreach ($array as $key => $value) {
        //echo $key;
        if($headkey!='' && !is_integer($headkey)){
            if(!is_integer($key)){
                if (is_array($value) || is_object($value)) {
                    if($pkey!='')
                       $parentkey=$pkey."->".$key;
                    else 
                        $parentkey=$key;
                        foreach($value as $kk=>$val){
                            foreach($val as $kk1=>$val1){
                                $keys[]=$parentkey."->".$kk1;
                            }
                        }
                        //$keys[]=$parentkey."->".$key;
                }else{
                    $keys[] = $pkey."->".$key;
                    $hkey=$headkey."->".$key;
                }
            }
        }
        else{
            if(!is_integer($key)){
                if($pkey!='')
                    $parentkey=$pkey."->".$key;
                else 
                    $parentkey=$key;
                if (is_array($value) || is_object($value)) {
                    if($pkey!='')
                        $parentkey=$pkey."->".$key;
                    else
                        $parentkey=$key;
                        foreach($value as $kk=>$val){
                            //print_r($val);echo "==========";
                            foreach($val as $kk1=>$val1){
                                $keys[]=$parentkey."->".$kk1;
                            }
                        }
                        $hkey=$key;
                }else{
                    $keys[]=$key;
                }
            }
        }
        
        if (is_array($value) || is_object($value)) {
            echo $key."-----".$hkey."<br>";
            $keys = array_merge($keys, array_keys_multi($value,$hkey,$key));
        }
    }
    return $keys;
}
$k=array_keys_multi($array,'','');
print_r($k);
I need output as an array with the following key paths (notice no numeric keys are retained):
[
    "client",
    "gateWay",
    "store",
    "valid",
    "po",
    "additionalPO",
    "customerNotes",
    "orderItems->item",
    "orderItems->quantity",
    "orderItems->supplierLotNo",
    "orderItems->customsValue",
    "orderItems->customsDescription",
    "orderItems->hsCode",
    "shippingInfos->address->city",
    "shippingInfos->address->country",
    "shippingInfos->address->postalCode",
    "shippingInfos->address->state",
    "shippingInfos->address->streetAddress1",
    "shippingInfos->address->streetAddress2",
    "shippingInfos->contact->company",
    "shippingInfos->contact->email",
    "shippingInfos->contact->firstName",
    "shippingInfos->contact->lastName",
    "shippingInfos->contact->phoneNo",
    "shippingInfos->ServiceId",
    "shippingInfos->thirdPartyAccountNo",
    "shippingInfos->signatureConfirmation",
    "shippingInfos->saturdayDelivery"
]
How can I achieve this?