node-red getting data from api and to sort

I have a little code to traite and sort some data get by api, my probleme but actually is that's applying on first array, could you please help me to resolve my problem ?

downlinks = [];

for (var i = 0; i < msg.payload.length; i++) {
    
    downlink = {};
    downlink.eui = msg.payload[i].valve_EUI;

    if (msg.payload[i].System_Activated === null ) {
        downlink.payload = new Buffer("00", "hex");
    } else {
        downlink.payload = new Buffer( "01", "hex");
    }
     

    downlink.port = 1;
    downlink.ack = true;
    downlink.RxWnd = 1;

    downlinks.push(downlink);
}

return downlinks;