Wsrtjtyk

I have a Flask-SocketIO Webapp where some data is generated by my Python script and sent to my JS Frontend. I'm now trying to put that data on a chart.
Here is what it should look like: the user opens the webpage and he should see the data updating, but he also should see the data from BEFORE he opened the webpage, so i need BOTH real-time/updated and past data.
Now the big problem is that i managed to put a real-time chart but i have no idea. When i open my webpage i can see the chart updating but i can't see past data on the chart, i literally tried everything.

Here is the javascript part of the code that i made, and here you can find the rest of the code (Python part + html part)

$(document).ready(function() {

  //connect to the socket server.

  var socket = io.connect('http://' + document.domain + ':' + location.port + '/test');

  var numbers_received = ;





  //receive details from server

  socket.on('newnumber', function(msg) {

    console.log("Received" + msg.number);

    //maintain a list of ten numbers

    if (numbers_received.length >= 1) {

      numbers_received.shift()

    }





    numbers_received.push(msg.number);

    numbers_string = '';

    for (var i = 0; i < numbers_received.length; i++) {

      numbers_string = numbers_string + '<p>' + numbers_received[i].toString() + '</p>';

    }

    $('#log').html(numbers_string);

  });













  function getData() {



                }

                Plotly.plot('chart',[{

                    y:[numbers_received[1]],

                    type:'line'

                }]);



                console.log('TEST' + numbers_received[0]);



                var cnt = 0;

                setInterval(function(){

                    Plotly.extendTraces('chart',{ y:[[numbers_received[0]]]}, [0]);

                    cnt++;

                    if(cnt >10000000) {

                        Plotly.relayout('chart',{

                            xaxis: {

                                range: [cnt-9,cnt]

                            }

                        });

                    }

                },15);



});

What should i do? Quit trying to use a Javascript library for my chart and use a Python library and generate the chart straight from Python (was thinking of re-making the entire app on Python Dash but it's not free)? Work on my Javascript code until i find a way, implying that it's possible? Just use another library?

Please, every little piece of help is highly appreciated, i have been trying to go forward with this for a week but i just can't find a way, thanks in advance