Need help with Json.stringify

Hi Everyone i'm Rick 22 years and I'm new here.

i got a problem I do not fully understand it what i have to do. can someone help me with this?

what i have to do is this:
Never create JSON strings manually, use JSON.stringify for this.

and he is talking about this code:

function saveState() {
    submitData('[{"lane 1": ' + getLaneState('lane1') + ',"lane 2": ' + getLaneState('lane2') + ',"lane 3": ' + getLaneState('lane3') + ',"lane 4": ' + getLaneState('lane4') + '}]');
}

Code (markup):

is this what i have to do? :

function saveState() {


    var myJSON = JSON.stringify(obj);

    var obj = submitData('[{"lane 1": ' + getLaneState('lane1') + ',"lane 2": ' + getLaneState('lane2') + ',"lane 3": ' + getLaneState('lane3') + ',"lane 4": ' + getLaneState('lane4') + '}]');
}

Code (markup):

 

Hello Rick
I think you have to explain more. Assuming what the submitData() function does is to return a JSON object, then yes you may execute

var myJSON = JSON.stringify(obj);

Code (JavaScript):

AFTER submitData() line but not before it.

 

its a function

function submitData(data) {
    var xhr = new XMLHttpRequest();
    var url = "savestate.php";
    xhr.open("POST", url, true);
    xhr.setRequestHeader("Content-Type", "application/json");
    xhr.onreadystatechange = function () {
        if (xhr.readyState === 4 && xhr.status === 200) {
            console.log(xhr.responseText);
        }
    };
    xhr.send(data);
}



function saveState() {


    var myJSON = JSON.stringify(obj);

    var obj = submitData('[{"lane 1": ' + getLaneState('lane1') + ',"lane 2": ' + getLaneState('lane2') + ',"lane 3": ' + getLaneState('lane3') + ',"lane 4": ' + getLaneState('lane4') + '}]');
}

Code (markup):