Displaying line chart for multiple datasets using chart.js

Question

I have to display a line chart with two different datasets in one single chart. After execution of query I got the plan_plan and actual_plan of the following form.

plan_plan = 0: {week: "46", planned_del: "20"}
               1: {week: "53", planned_del: "94"}

actual_plan = 0: {week: "8", actual_del: "1"}

javascript part:

function show_Graph()
        {
            {
                var plandata = <?php echo json_encode($plan_plan); ?>;
                var actualdata = <?php echo json_encode($actual_plan); ?>;

                   console.log(plandata);
                     var labels = [];
                    var plandel = [];
                    var actualdel = [];

      for (var i in plandata) {
                        labels.push(plandata[i].week);
                        plandel.push(plandata[i]);
                      }
    for (var j in actualdata) {
                       labels.push(actualdata[j].week);
                        actualdel.push(actualdata[j]);
                      }

                    var chartdata = {
                        labels: labels,

                        datasets: [

                            {
                                label: "Planned Deliverables",
                                fill: false,
                                borderColor: "rgba(255, 0, 0, 1)",
                                pointHoverBackgroundColor: "rgba(255, 0, 0, 1)",
                                data: plandel
                            },
                            {
                                label: "Actual Deliverables",
                                fill: false,
                                backgroundColor: "rgba(0, 255, 0, 0.75)",
                                borderColor: "rgba(0, 255, 0, 1)",
                                pointHoverBackgroundColor: "rgba(0, 255, 0, 1)",
                                pointHoverBorderColor: "rgba(0, 255, 0, 1)",
                                data: actualdel

                            }


                        ]

                    };

                    var graphTarget = $("#scurve_chart");

                  var barGraph = new Chart(graphTarget, {
                        type: 'line',
                        data: chartdata,
                        options: {
                            elements: {
                    point:{
                        radius: 1,
                    }
                },


        scales: {
            yAxes: [{
                ticks: {
                    beginAtZero: true
                }
            }],
            xAxes: [{
            barValueSpacing: 2,
            barPercentage: 0.2
        }]
        }
    }
                    });

            }}

I want to get the week in x axis and then planned_del and actual_del data in y axis which can be shown as line chart. And also should show a single point entry even when there is no data points to be connected.

Answer 1

One way for achieving this, would be to defined data.labels as an array of numbers from 0 to 53.

labels: [0, 1, 2, ... 53]

The data inside the two datasets would then only contain the definitions of individual points .

data: [{ x: 46, y: 20 }, { x: 53, y: 94 }] // plandata 
...
data: [{ x: 8, y: 1}] // actualdata 

Here's the JavaScript part that illustrates how the desired result can be obtained.

 var plandata = [{ week: "46", planned_del: "20" }, { week: "53", planned_del: "94" }]; var actualdata = [{ week: "8", actual_del: "1" }]; new Chart("scurve_chart", { type: 'line', data: { labels: Array.from(new Array(54), (x, i) => i), datasets: [{ label: "Planned Deliverables", fill: false, borderColor: "rgba(255, 0, 0, 1)", pointHoverBackgroundColor: "rgba(255, 0, 0, 1)", data: plandata.map(o => ({ x: Number(o.week), y: Number(o.planned_del)})) }, { label: "Actual Deliverables", fill: false, backgroundColor: "rgba(0, 255, 0, 0.75)", borderColor: "rgba(0, 255, 0, 1)", pointHoverBackgroundColor: "rgba(0, 255, 0, 1)", pointHoverBorderColor: "rgba(0, 255, 0, 1)", data: actualdata.map(o => ({x: Number(o.week), y: Number(o.actual_del)})) } ] }, options: { tooltips: { callbacks: { title: (tooltipItem, data) => "Week " + data.datasets[tooltipItem[0].datasetIndex].data[tooltipItem[0].index].x } }, scales: { yAxes: [{ ticks: { beginAtZero: true } }], xAxes: [{ ticks: { min: 0, max: 53, stepSize: 1 } }] } } });

 <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.bundle.js"></script> <canvas id="scurve_chart" height="90"></canvas>