var chart = new Chart(ctx, {

                type: 'line',
                data: {
                labels: [],
                datasets: [{
                    label: "Swiatlo",
                    borderColor: "#FF5733",
                    data: [],
                    fill: false,
                    pointStyle: 'circle',
                    backgroundColor: '#3498DB',
                }]
                },

                options: {}

            });
            socket.on('temp', function(data) {
                console.log(data.temp);
                chart.data.datasets.forEach((dataset) => {
                        dataset.data.push(data.temp);
                    });
                chart.update();
            });